speed skater vs ice-skater

speed skater and ice-skater both are nouns.

Word	Noun	Adjective	Verb	Adverb
speed skater	Yes	No	No	No
ice-skater	Yes	No	No	No

As nouns, ice-skater is a hypernym of speed skater; that is, ice-skater is a word with a broader meaning than speed skater:

speed skater: an ice-skater who races competitively; usually around an oval course
ice-skater: someone who engages in ice skating

speed skater (noun)	ice-skater (noun)
an ice-skater who races competitively; usually around an oval course	someone who engages in ice skating