Relative Pronoun · اسم موصولA relative pronoun is a word like 'the ones who' that hooks a whole describing sentence onto a group. ٱلَّذِينَ means 'the ones who', and the words after it — 'have purchased error' — describe them. L5 · R13

Predicate (Khabar) · خبرThe predicate is the part that tells you something about the topic. The topic was أُو۟لَٰٓئِكَ 'those'; ٱلَّذِينَ 'the ones who…' is what is said about them — those are the ones who purchased error. L6 · R3

Verb · فعلA verb is a word for an action tied to a time. ٱشْتَرَوُا۟ names an action — buying, purchasing — from the root شري, to buy. L1 · R7

Past Tense Verb · فعل ماضٍA past tense verb describes a completed action, marking who did it by an ending on the base. The ending وُا۟ on ٱشْتَرَوُا۟ marks 'they' as the buyers: 'they purchased'. L8 · R2

Weak Verb · فعل معتلA weak verb has a و or ي among its root letters, which love to soften or vanish. From the root شري, the weak ي has melted away before the ending of ٱشْتَرَوُا۟, hiding that root letter. L24 · R1

Form VIII Verb · اِفْتَعَلَA Form VIII verb tucks an extra تـ just after the first root letter. ٱشْتَرَوُا۟, from the root شري, shows that تـ after its first letter ش, marking it as Form VIII. L13 · R4

Attached Pronoun · ضمير متصلAn attached pronoun is a mini-word glued onto the end of a verb. The ending وُا۟ on ٱشْتَرَوُا۟ is such a suffix, standing for 'they' — the buyers. L3 · R6

Doer (Fa'il) · فاعلThe doer is the one performing the action, so it stands in the nominative — the doer's form, usually shown by a ḍammah ـُ, a small curl above the last letter. The ending وُا۟ on ٱشْتَرَوُا۟ is that doer, 'they'; on this attached pronoun the shape is fixed, so no ḍammah appears, but the role it fills is the nominative one. L9 · R4

Definite Article · أل التعريفThe definite article is the prefix ٱل ('the') fixed to the front of a noun to mark a specific, known thing. Here it marks ضَّلَٰلَةَ as 'the error' they took on. L2 · R9

Noun · اسمA word that accepts the prefix ٱل ('the') is a noun — a naming word. This word carries that prefix and names a thing, 'error', from the root ضلل, to go astray. L1 · R1

Feminine Noun · اسم مؤنثA feminine noun is a naming word Arabic treats as 'she', most often marked by a ة at its end. ضَّلَٰلَةَ ends in that ة, so it is treated as feminine. L2 · R1

Accusative · منصوبThe accusative is the ending a naming word takes when the action lands on it, usually shown by a fathah ـَ — a small slanted stroke above the last letter. ٱلضَّلَٰلَةَ ends in that fathah ـَ, marking it as what was purchased. L2 · R11

Direct Object · مفعول بهThe direct object is the thing the action lands on, and it takes the accusative — the ending shown by a fathah ـَ, a small stroke above the last letter. ٱلضَّلَٰلَةَ carries that fathah ـَ and is what they bought — the error. L9 · R3

Preposition · حرف جرA preposition is a little word that relates one thing to another and pulls the noun right after it into the genitive — the ending for a noun after a preposition, usually shown by a kasrah ـِ, a small stroke below the last letter. The prefix بِ 'for/with' does that here, setting guidance as the price given up. L4 · R1

Definite Article · أل التعريفThe definite article is the prefix ٱلْ ('the') fixed to the front of a noun to mark a specific, known thing. Here it marks هُدَىٰ as 'the guidance' they exchanged away. L2 · R9

Noun · اسمA word that accepts the prefix ٱلْ ('the') is a noun — a naming word. This word carries that prefix and names a thing, 'guidance', from the root هدي, to guide. L1 · R1

Masculine Noun · اسم مذكرArabic treats every naming word as grammatically 'he' or 'she'. This word carries no feminine marker such as a ة at its end, so it falls to the default and is treated as 'he': a masculine noun. L2 · R3

Genitive · مجرورThe genitive is the ending a naming word takes after a preposition, usually shown by a kasrah ـِ — a small stroke below the last letter. هُدَىٰ stands in that genitive role after the preposition بِ 'for'; its ending rests on a final long vowel that holds the case silently, so no kasrah is written, but the role it fills is the genitive one. L2 · R12

Resumptive Particle · حرف استئنافA resumptive particle is a وَ or فَ that begins a fresh statement after a pause or shift, closer to opening a new sentence than a plain 'and'. The prefix فَ here starts the new point: 'so their transaction has brought no profit'. L14 · R1

Particle · حرفA particle is a small helper word with no meaning standing alone; it takes no ending and does not name or act. مَا is such a helper word here. L1 · R8

Negation Particle · حرف نفيA negation particle is a word meaning 'not'. مَا here negates the past-tense verb after it: 'their transaction did not profit'. L4 · R5

Verb · فعلA verb is a word for an action tied to a time. رَبِحَت names an action — profiting — from the root ربح, to gain through trade. L1 · R7

Past Tense Verb · فعل ماضٍA past tense verb describes a completed action, its base form carrying no prefix. رَبِحَت has no prefix, and its ending تْ marks a 'she' doer — the transaction (a feminine noun): 'it profited'. L8 · R2

Noun · اسمA noun is a naming word for a thing. تِّجَٰرَتُ names a thing — commerce, a transaction — from the root تجر, to trade. L1 · R6

Feminine Noun · اسم مؤنثA feminine noun is a naming word Arabic treats as 'she', most often marked by a ة at its end. تِّجَٰرَتُ carries that ة (here written before the pronoun), so it is treated as feminine — which is why its verb رَبِحَت took the 'she' ending تْ. L2 · R1

Nominative · مرفوعThe nominative is the ending a naming word takes when it is the one doing the action, usually shown by a ḍammah ـُ — a small curl above the last letter. تِّجَٰرَتُ ends in that ḍammah ـُ, marking their transaction as the doer of the profiting. L2 · R10

Doer (Fa'il) · فاعلThe doer is the one performing the action, and it stands in the nominative — the doer's form, shown by a ḍammah ـُ above the last letter. تِّجَٰرَتُ carries that ḍammah ـُ and is the one that did — or here, with 'not', did not — profit. L9 · R2

Attached Pronoun · ضمير متصلAn attached pronoun is a mini-word for 'their' glued onto the end of a noun. The ending هُمْ on تِّجَـٰرَتُهُمْ stands for 'their', naming whose transaction it is. L3 · R6

Possessive (Idafa) · مضاف إليهA possessive (iḍāfah) chains an owner onto the thing owned, and the owner carries the genitive — the owner's ending, usually shown by a kasrah ـِ, a small slanted stroke below the last letter. The ending هُمْ 'their' is that owner glued onto تِّجَٰرَتُ; a pronoun like هُمْ keeps its fixed written shape, so no kasrah appears on it — the genitive is the role its owner slot carries: 'their transaction'. L5 · R5

Conjunction · حرف عطفA conjunction is a small joining word like 'and' or 'nor' that ties one part of speech to another. The prefix وَ here joins this new negation to the one before: 'nor were they guided'. L4 · R4

Particle · حرفA particle is a small helper word with no meaning standing alone; it takes no ending and does not name or act. مَا is such a helper word here. L1 · R8

Negation Particle · حرف نفيA negation particle is a word meaning 'not'. مَا here negates what follows: 'they were not guided'. L4 · R5

Verb · فعلA verb is a word for an action or state tied to a time. كَانُوا۟ names a state — being — from the root كون, to be or exist. L1 · R7

Past Tense Verb · فعل ماضٍA past tense verb describes a completed state, marking who by an ending on the base. The ending وا۟ on كَانُوا۟ marks 'they': 'they were'. L8 · R2

Weak Verb · فعل معتلA weak verb has a و or ي among its root letters, which love to turn into a long 'ā'. From the root كون, the middle و has become the long 'ā' of كَانُوا۟, hiding that root letter. L24 · R1

Kāna Verb · كان وأخواتهاكَانَ 'was' is an incomplete verb: it needs both a topic and a comment, keeping its topic nominative — the ḍammah ـُ form — while pushing its comment into the accusative, usually a fathah ـَ. Here its topic is the hidden 'they' in its ending, and its comment is 'guided', which takes that accusative ending. L18 · R3

Attached Pronoun · ضمير متصلAn attached pronoun is a mini-word glued onto the end of a verb. The ending وا۟ on كَانُوا۟ is such a suffix, standing for 'they' — the topic كَانَ speaks about. L3 · R6

Noun · اسمA noun is a naming word for a person or thing. مُهْتَدِينَ names people — guided ones — from the root هدي, to guide. L1 · R6

Masculine Noun · اسم مذكرArabic treats every naming word as grammatically 'he' or 'she'. This word carries no feminine marker such as a ة at its end, so it falls to the default and is treated as 'he': a masculine noun. L2 · R3

Plural Noun · جمعA plural noun refers to three or more. The masculine sound plural in the accusative adds the ending ـِينَ. مُهْتَدِينَ ends in ـِينَ, so it names many guided ones, not just one. L2 · R6

Accusative · منصوبThe accusative is the ending a naming word takes as the comment of كَانَ; for this kind of plural that ending is ـِينَ rather than the nominative ـُونَ. مُهْتَدِينَ carries that ـِينَ ending, marking it as the accusative comment: 'they were not guided ones'. L2 · R11

Active Participle · اسم فاعلAn active participle is a naming word built from a verb's root to name the one holding the action, and for the derived patterns it opens with مُـ. Built from the root هدي (to guide), مُهْتَدِينَ opens with مُـ and names those who are guided. L11 · R3