ascender vs climber

ascender and climber both are nouns.

Word	Noun	Adjective	Verb	Adverb
ascender	Yes	No	No	No
climber	Yes	No	No	No

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

Other hyponyms of ascender include mounter.

ascender (noun)	climber (noun)
(printing) the part of tall lowercase letters that extends above the other lowercase letters	an iron spike attached to the shoe to prevent slipping on ice when walking or climbing
a lowercase letter that has a part extending above other lowercase letters	someone who climbs as a sport; especially someone who climbs mountains
someone who ascends	someone seeking social prominence by obsequious behavior
	someone who ascends on foot
	a vine or climbing plant that readily grows up a support or over other plants