Claiming or demanding a position of distinction or merit, especially when unjustified.
Making or marked by an extravagant outward show; ostentatious. See Synonyms at showy.
– from dictionary.reference.com
I’ve always thought pretentiousness derives from behaviour, not intellectualism. So I was surprised that my down-to-earth wife has turned pretentious. I don’t think so unless I have turned too.