accept vs knuckle under

accept and knuckle under both are verbs.

Word	Noun	Adjective	Verb	Adverb
accept	No	No	Yes	No
knuckle under	No	No	Yes	No

As verbs, knuckle under is a hyponym of accept; that is, knuckle under is a word with a more specific, narrower meaning than accept:

accept (verb)	knuckle under (verb)
consider or hold as true	consent reluctantly
react favorably to; consider right and proper
tolerate or accommodate oneself to
be sexually responsive to, used of a female domesticated mammal
give an affirmative reply to; respond favorably to
receive willingly something given or offered
take on as one's own the expenses or debts of another person
admit into a group or community
receive (a report) officially, as from a committee
make use of or accept for some purpose
be designed to hold or take