しなく

not do, not make

→ 為る
し do + なく Negative
verb · informal Rare #42,880
not do, not make A conjugated form of する, used before なる to mean “stop doing” or “no longer do,” and before はない in しなくもない to mean “not entirely not”; the meaning depends on what follows.
JA: 今日は何もしなくていい。
EN: You don't have to do anything today.
Conjugation of 為る
Imperfect
Present
Desiderative future
Irrealis
Quotative
Potential present
Desiderative present
Potential future
Subjunctive present
Imperative present
Jussive

注意すればするほど、ミスをしなくなる。

The more careful you are, the fewer mistakes you make.

パソコンが起動しなくなりました。

My computer won't turn on anymore.

君にそう強く言われるとそんな気がしなくもないけれど。

When you put it that strongly, I suppose I can kind of see it that way.

もう二度と町のことは気にしなくなりました。

I stopped caring about the town altogether.