pedaler vs unicyclist

pedaler and unicyclist both are nouns.

Word	Noun	Adjective	Verb	Adverb
pedaler	Yes	No	No	No
unicyclist	Yes	No	No	No

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

Other hyponyms of pedaler include bicycler, bicyclist, biker, cyclist, wheeler.

pedaler (noun)	unicyclist (noun)
a person who rides a pedal-driven vehicle (as a bicycle)	a person who rides a unicycle