noun, na-adjective
coward; gutless person; weakling
A derogatory term for someone lacking guts, spirit, or perseverance. Often used as an insult.
あいつは根性なしだから、すぐ諦める。
That guy is a gutless coward, so he gives up right away.
そんな根性なしのやり方じゃ成功できないよ。
You can't succeed with such a spineless approach.
Compound of 根性 (こんじょう, 'guts, willpower') + なし ('without').