smell vs stink

smell and stink both are nouns.

Word	Noun	Adjective	Verb	Adverb
smell	Yes	No	Yes	No
stink	Yes	No	Yes	No

As nouns, stink is a hyponym of smell; that is, stink is a word with a more specific, narrower meaning than smell:

smell: the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form
stink: a distinctive odor that is offensively unpleasant

As verbs, stink is a hyponym of smell; that is, stink is a word with a more specific, narrower meaning than smell:

Other hyponyms of smell include reek, salute.

smell (noun)	stink (noun)
the act of perceiving the odor of something	a distinctive odor that is offensively unpleasant
any property detected by the olfactory system
the faculty that enables us to distinguish scents
the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form
the general atmosphere of a place or situation and the effect that it has on people

smell (verb)	stink (verb)
become aware of not through the senses but instinctively	smell badly and offensively
emit an odor	be extremely bad in quality or in one's performance
inhale the odor of; perceive by the olfactory sense
smell bad
have an element suggestive (of something)