I know that feeling! I read a lot as a kid, and I'd pick up words from context but not get their meanings right, and that got embarrassing. So I talked my folks into getting me the biggest, meanest dictionary they could lay hands on, in order to avoid embarrassing myself further. Little did I know this would lead me down a path of linguistic pedantry from which I'd never be able to return.

Was the word you were after perhaps 'pertinent'?