不當

unsuitable / improper / inappropriate

no; not so / (bound form) not; un-

to be / to act as / manage / withstand / when / during / ought / should / match equally / equal / same / obstruct / just at (a time or place) / on the spot / right / just at

at or in the very same... / suitable / adequate / fitting / proper / to replace / to regard as / to think / to pawn / (coll.) to fail (a student)

to regret one's past deeds (idiom)

useless / regard as useless

a person who doesn't manage a household would not be aware how expensive it is (idiom)

unjust enrichment

not important / of no consequence

disproportionate punishment / the punishment is harsher than the crime

lit. unbeatable by even 10,000 men (idiom) / fig. extremely brave and strong

to fail to keep to one's word / to break a promise

not regard as a matter (of any importance)