exhaust vs indulge

exhaust is a noun but indulge is not a noun.

Word	Noun	Adjective	Verb	Adverb
exhaust	Yes	No	Yes	No
indulge	No	No	Yes	No

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

exhaust (noun)	indulge (noun)
system consisting of the parts of an engine through which burned gases or steam are discharged
gases ejected from an engine as waste products

exhaust (verb)	indulge (verb)
wear out completely	yield (to); give satisfaction to
eliminate (a substance)	enjoy to excess
use up the whole supply of	treat with excessive indulgence
use up (resources or materials)	give free rein to
deplete