separation vs sifting

separation and sifting both are nouns.

Word	Noun	Adjective	Verb	Adverb
separation	Yes	No	No	No
sifting	Yes	No	No	No

As nouns, sifting is a hyponym of separation; that is, sifting is a word with a more specific, narrower meaning than separation:

Other hyponyms of separation include threshing, winnow, winnowing.

separation (noun)	sifting (noun)
the social act of separating or parting company	the act of separating grain from chaff
the act of dividing or disconnecting
(law) the cessation of cohabitation of man and wife (either by mutual agreement or under a court order)
sorting one thing from others
the distance between things
coming apart
the termination of employment (by resignation or dismissal)
the space where a division or parting occurs
the state of lacking unity