The correct synonym of 'Pomposity' is-

Pomposity
(noun)

English Meaning: a pompous gesture, habit, or act
Bangla Meaning: দাম্ভিকতা; আড়ম্ভরতা; আত্মম্বরিতা।
 
Synonyms: arrogance, assumption, bumptiousness, consequence, haughtiness, hauteur, high horse, huffiness, imperiousness
Antonyms: self-importance, loftiness, pretense, presumptuousness, pretentiousness, peremptoriness

Example Sentence: 
1. His over-the-top trophy mansion should give you some idea of his pomposity.

Source: Website Lecture.