noun which may take the genitive case particle 'no'
compulsory; unavoidable; without choice
Used to describe a situation where one has no say or cannot refuse; often in the phrase 否応なしに (willy-nilly, whether one likes it or not).
否応なしにその仕事を引き受けさせられた。
I was forced to take on that job whether I liked it or not.
戦争になれば、否応なしに巻き込まれる。
If war breaks out, you'll be dragged in willy-nilly.
Compound of 否 (いや, 'no') + 応 (おう, 'yes') + なし ('without'), literally 'without yes or no', meaning without the ability to say yes or no.