Capricorn vs doer

Capricorn and doer both are nouns.

Word	Noun	Adjective	Verb	Adverb
Capricorn	Yes	No	No	No
doer	Yes	No	No	No

As nouns, doer is a hypernym of Capricorn; that is, doer is a word with a broader meaning than Capricorn:

Other hypernyms of Capricorn include actor, worker.

Capricorn (noun)	doer (noun)
the tenth sign of the zodiac; the sun is in this sign from about December 22 to January 19	a person who acts and gets things done
a faint zodiacal constellation in the Southern Hemisphere; between Sagittarius and Aquarius
(astrology) a person who is born while the sun is in Capricorn