foul-smelling vs smelly

foul-smelling and smelly both are adjectives.

Word	Noun	Adjective	Verb	Adverb
foul-smelling	No	Yes	No	No
smelly	No	Yes	No	No

As adjectives, foul-smelling and smelly are synonyms defined as:

Other synonyms of foul-smelling include fetid, foetid, foul, funky, ill-scented, noisome, stinking.

foul-smelling (adjective)	smelly (adjective)
offensively malodorous	offensively malodorous