The adjective pretentious means someone or something that is trying to present or sound more valuable than they are.
Synonyms are snobbish, showy, arty, or exaggerated.
The word origins from French prétentieux (17th century), from prétention meaning “pretension” and Medieval Latin pretentionem meaning “pretension”, noun of action from past participle stem of Latin praetendere.
He has a pretentious attitude.
I find it hard to agree with her pretentious suggestions.
After becoming successful, he became a pretentious one.