كَذَّبَتْ ثَمُودُ بِطَغْوَىٰهَآ
Sentence structure
كَذَّبَتْ is a feminine-singular Form II perfect and ثَمُودُ its nominative subject. بِطَغْوَىٰهَا is linked to the verb; attached هَا is the possessor of طَغْوَىٰ.
Ayah summary
The people of Thamud denied the truth because of their rebellion.
كَذَّبَتْ — Denied
Grammar: A Form II third-person feminine-singular perfect whose explicit subject follows.
ثَمُودُ — Thamud
Grammar: A proper noun functioning as the nominative subject of كَذَّبَتْ.
بِطَغْوَىٰهَآ — by their transgression
Grammar: بِ is a preposition; طَغْوَىٰ is genitive in position and attached هَا its possessor. This phrase is linked to «كَذَّبَتْ».