もしない・
Attach もしない to a verb stem to stress that someone does not even perform an expected or minimal action. Use もしないで when the sentence continues with what happens despite that omission.
What the construction adds
The speaker treats the omitted action as something basic, easy, expected, or appropriate. The も adds the sense of “even,” so the sentence often carries criticism or surprise rather than simply reporting that an action did not occur.
Expected actions left undone
The context should make it clear why the missing action is noteworthy.
彼は説明書を読みもしないで、その機械は故障していると決めつけた。
Without even reading the manual, he concluded that the machine was broken.
Analyze何度尋ねても、担当者は答えもしない。
Despite repeated questions, the person in charge does not even answer.
Analyze彼女は地図を見もしないで、迷わず会場に着いた。
She reached the venue without getting lost, without even looking at a map.
AnalyzeHere the tone is surprised and impressed rather than critical.
Using the continuing form
もしないで connects the omitted action to what happened next. It commonly implies that the first action should normally have come before the second.
彼は理由を聞きもしないで、申請を却下した。
He rejected the application without even asking the reason.
AnalyzeFailure to act versus forceful denial
もしない highlights failure to perform even a basic or expected action. By contrast, やしない or はしない more directly and forcefully rejects the idea that an action will occur.
そんな根拠のない噂は信じやしない。
I would never believe such a baseless rumor.
AnalyzeThis is forceful denial, not criticism that someone failed to take a minimal expected action.
More examples
母が何度呼んでも、弟は振り向きもしない。
No matter how many times his mother calls, my younger brother does not even turn around.
Analyze新人なのに、メモを取りもしない。
Despite being new, the employee does not even take notes.
Analyze子どもは靴を脱ぎもしないで、部屋に上がった。
The child entered the room without even taking off their shoes.
Analyze彼は説明を最後まで聞きもしないで、無理だと言った。
He said it was impossible without even listening to the explanation to the end.
Analyze彼女はメモを見もしないで、全員の名前を言い当てた。
Without even looking at her notes, she correctly named everyone.
Analyze店員は客の顔を見もしないで、機械的に答えた。
The clerk answered mechanically without even looking at the customer.
Analyze