tumbler vs gymnast

tumbler and gymnast both are nouns.

Word	Noun	Adjective	Verb	Adverb
tumbler	Yes	No	No	No
gymnast	Yes	No	No	No

As nouns, gymnast is a hypernym of tumbler; that is, gymnast is a word with a broader meaning than tumbler:

tumbler (noun)	gymnast (noun)
pigeon that executes backward somersaults in flight or on the ground	an athlete who is skilled in gymnastics
a glass with a flat bottom but no handle or stem; originally had a round bottom
a movable obstruction in a lock that must be adjusted to a given position (as by a key) before the bolt can be thrown
a gymnast who performs rolls and somersaults and twists etc.