Libra vs doer

Libra and doer both are nouns.

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

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

Other hypernyms of Libra include actor, worker.

Libra (noun)	doer (noun)
the seventh sign of the zodiac; the sun is in this sign from about September 23 to October 22	a person who acts and gets things done
a small faint zodiacal constellation in the Southern Hemisphere; between Virgo and Scorpius
(astrology) a person who is born while the sun is in Libra