طَغْوَا

A word in the Arabic language will either be 1) a verb or 2) a noun or 3) a particle – طَغْوَا is a noun

A noun may either be 1) Definite or indefinite 2) Masculine or feminine 3) Singular, dual or plural 4) Nominative, accusative or genitive

الطَّغْوَى is the natural state of this definite noun and it remains الطَّغْوَى even though it is in the genitive case due to: 1) a preposition that precedes it or 2) a possessed noun that precedes it or 3) it’s a noun of dependent declension a) نَعْتٌ / صِفَطٌ adjectives b) التَّوْكِيْدُ emphatic c) المَعْطُوْفٌ conjunction d) البَدَلُ synonym

because the third radical in الطَّغْوَى is a weak letter (و or ي) and weak letters do not show their endings, their endings have to be estimated (deduced by reason)

الطَّغْوَى loses it’s definite article ال, changing to طَغْوَا due to it being a possessed noun

Excess of impiety, Extreme wickedness

To transgress, wander from its orbit, exceed the bound

مَعْرِفَةٌجَمْعٌمُذَكَّرٌمَجْرُوْرٌط غ ىبَاب فَتَحَطَغَى يَطْغَىفَعْلَىاسْمٌالْجَمْعُ التَّكْثِيْرُ
DefiniteCollective pluralMasculineGenitiveRootTransgressionفPatternNounBroken plural
Surah/Below is the 1 verse in the holy Quran containing the nounطَغْوَا
Verse 
91-11Thamud denied by their transgressionكَذَّبَتْ ثَمُوْدُ بِطَغْوَاهَآ