trim vs thin out

trim is a noun but thin out is not a noun.

Word	Noun	Adjective	Verb	Adverb
trim	Yes	Yes	Yes	No
thin out	No	No	Yes	No

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

As verbs, thin out is a hypernym of trim; that is, thin out is a word with a broader meaning than trim:

trim (noun)	thin out (noun)
cutting down to the desired size or shape
a decoration or adornment typically on the edge of a garment
attitude of an aircraft in flight when allowed to take its own orientation
a state of arrangement or appearance

trim (adjective)	thin out (adjective)
severely simple in line or design
thin and fit
characterized by order and neatness; free from disorder
neat and smart in appearance

trim (verb)	thin out (verb)
cut down on; make a reduction in	make sparse
adjust (sails on a ship) so that the wind is optimally used	become sparser
cut closely	lessen the strength or flavor of a solution or mixture
cultivate, tend, and cut back the growth of
remove the edges from and cut down to the desired size
decorate (food), as with parsley or other ornamental foods
decorate, as with ornaments
be in equilibrium during a flight
balance in flight by regulating the control surfaces