transitive verb

1. 1. to blow the chaff from (grain) by wind or a forced current of air
   2. to blow off (chaff) in this manner
2. to blow away; scatter
3. to analyze or examine carefully in order to separate the various elements; sift
4. 1. to separate out or eliminate (the poor or useless parts)
   2. to sort out or extract (the good or useful parts)
5. Now Rare to fan with or as with the wings

Etymology: ME winewen < OE windwian, to winnow < wind, wind

intransitive verb

noun

1. the act of winnowing
2. an apparatus for winnowing