Time, Manner, Place

Every so often, I use a word which makes everyone go "eh?". Often this is because I'm using regional words in the wrong region (and, in fairness, sometimes it's because I'm just indulging my taste for obscure words). But recently, I apologised for saying "playing hooky" (playing truant), and was told that this was in fact (a) well-known and (b) American. So I'm wondering... how many of the words I often avoid really are obscure northenisms. Are they in fact well known? Are they not actually northern, but instead, perhaps, words that were common when I was little/are common among kids but not grown ups, or something completely different?

( Help me out )