pursuit vs spelaeology

pursuit and spelaeology both are nouns.

Word	Noun	Adjective	Verb	Adverb
pursuit	Yes	No	No	No
spelaeology	Yes	No	No	No

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

Other hyponyms of pursuit include speleology, pigeon keeping.

pursuit (noun)	spelaeology (noun)
the act of pursuing in an effort to overtake or capture	the pastime of exploring caves
a diversion that occupies one's time and thoughts (usually pleasantly)	the scientific study of caves
an auxiliary activity
a search for an alternative that meets cognitive criteria