sideline vs spelaeology

sideline and spelaeology both are nouns.

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

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

Other hyponyms of sideline include speleology, pigeon keeping.

sideline (noun)	spelaeology (noun)
an auxiliary activity	the pastime of exploring caves
an auxiliary line of merchandise	the scientific study of caves
a line that marks the side boundary of a playing field

sideline (verb)	spelaeology (verb)
remove from the center of activity or attention; place into an inferior position