slim down vs slim

slim down is not an adjective while slim is an adjective.

Word	Noun	Adjective	Verb	Adverb
slim down	No	No	Yes	No
slim	No	Yes	Yes	No

As verbs, slim down and slim are synonyms defined as:

Other synonyms of slim down include melt off, reduce, slenderize, thin.

slim down (adjective)	slim (adjective)
	small in quantity
	being of delicate or slender build

slim down (verb)	slim (verb)
take off weight	take off weight