single out vs segregate

single out is not a noun while segregate is a noun.

Word	Noun	Adjective	Verb	Adverb
single out	No	No	Yes	No
segregate	Yes	No	Yes	No

As verbs, segregate is a hyponym of single out; that is, segregate is a word with a more specific, narrower meaning than single out:

single out: treat differently on the basis of sex or race
segregate: separate by race or religion; practice a policy of racial segregation

Other hyponyms of single out include insulate, isolate, hive off, redline, disadvantage, disfavor, disfavour.

single out (noun)	segregate (noun)
	someone who is or has been segregated

single out (verb)	segregate (verb)
select from a group	separate or isolate (one thing) from another and place in a group apart from others
treat differently on the basis of sex or race	divide from the main body or mass and collect
	separate by race or religion; practice a policy of racial segregation