1.to amend by removing words, passages, etc., deemed offensive or objectionable
2.to purge or cleanse of moral offensiveness.
"Oneir pinched a candle from the kitchets and read aloud from The Arabian Nights, which turned out to have been a remarkably good buy. "Unexpurgated" seemed to mean that all sorts of interestingly dirty bits had been put in."
-from The Lives of Christopher Chant by Diana Wynne Jones
winnew or winnow
1. To separate, and drive off, the chaff from by means of wind; to fan
2. To sift, as for the purpose of separating falsehood from truth; to separate, as had from good.
3. To beat with wings, or as with wings.[Poetic]
1. to get rid of (something undesirable or unwanted)
1. cull out: select desirable parts from a group or list
I'm trying to winnow the classes I want from this isufferably long list of courses I have yet to take, but it's taking such a long while that I might just take my finger and select them at random.