وَمَا هُوَ بِٱلْهَزْلِ
Sentence structure
وَ coordinates and مَا negates. هُوَ is the noun/topic, while بِٱلْهَزْلِ supplies the predicate; its بِ reinforces the negation.
Ayah summary
It is not a matter of jest but a truthful announcement.
وَمَا — And not
Grammar: وَ coordinates and مَا negates.
هُوَ — it
Grammar: A detached third-person masculine-singular pronoun functioning as the noun of مَا or as the topic, in one recognized grammatical reading.
بِٱلْهَزْلِ — (is) for amusement
Grammar: بِ is an extra preposition reinforcing negation, ٱل the definite article, and هَزْلِ genitive in form while the phrase supplies the predicate.