capableness vs overkill

capableness and overkill both are nouns.

Word	Noun	Adjective	Verb	Adverb
capableness	Yes	No	No	No
overkill	Yes	No	No	No

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

capableness: the quality of being capable -- physically or intellectually or legally
overkill: the capability to obliterate a target with more weapons (especially nuclear weapons) than are required

capableness (noun)	overkill (noun)
the quality of being capable -- physically or intellectually or legally	any effort that seems to go farther than would be necessary to achieve its goal
an aptitude that may be developed	the capability to obliterate a target with more weapons (especially nuclear weapons) than are required