1Used together with a negative verb or adjective to mean that something is not to a great degree — "not very," "not particularly," "not especially."
今日は大して忙しくないから、手伝えるよ。
I'm not very busy today, so I can help.
彼の話は大して面白くなかった。
His story wasn't particularly interesting.
大して期待していなかった試合が意外と面白かった。
A match I didn't expect much from turned out to be surprisingly interesting.
このセーターは大して高くなかったのに、とても暖かい。
This sweater wasn't very expensive, yet it's really warm.