Present, Future やむを得ない is [x] やむを得なくない is not [x] Past やむを得なかった was [x] やむを得なくなかった was not [x] Te-form, Continuative やむを得なくて is [x] and... やむを得なくなくて is not [x] and... Provisional やむを得なければ if it is [x] やむを得なくなければ if it is not [x] Conditional やむを得なかったら when/if it is [x] やむを得なくなかったら when/if it is not [x] Adverbial やむを得なく [x]-ly Noun form やむを得なさ [x]-ness