pedaller vs bicyclist

pedaller and bicyclist both are nouns.

Word	Noun	Adjective	Verb	Adverb
pedaller	Yes	No	No	No
bicyclist	Yes	No	No	No

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

Other hyponyms of pedaller include bicycler, biker, cyclist, wheeler, unicyclist.

pedaller (noun)	bicyclist (noun)
a person who rides a pedal-driven vehicle (as a bicycle)	a person who rides a bicycle