noun
not studying; without studying
Slang used mainly by students to describe taking a test or exam without having studied. Often used in phrases like ノー勉で受ける.
明日のテスト、ノー勉で受けるしかない。
I have no choice but to take tomorrow's test without having studied.
ノー勉だったけど、意外とできた。
I hadn't studied, but I did surprisingly well.