adverb · won't do; be out of the question

只给这么点钱肯定不行。

adverb · not work; not functioning correctly

这个老旧的机器已经不行了。

adverb · an expression used to refuse a request or indicate that a situation is unacceptable or forbidden

这事儿绝对不行，我们不能冒险。

adverb · be no good; not be capable

他在数学方面实在不行。