fetid vs foul-smelling

fetid and foul-smelling both are adjectives.

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

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

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

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