1An expression meaning that something is wrong or not good; similar to 'that's not acceptable' or 'that's bad.'
そんなことを他人の前で言うのは行けませんよ。
You mustn't say such things in front of others.
約束を破るのは行けません。
Breaking a promise is not acceptable.
2Used to indicate that something is hopeless or beyond help — 'it's past hope' or 'no use.'
この状況ではもう行けませんね、別の方法を考えましょう。
In this situation we're past hope; let's consider another approach.
大幅な損傷で修理は行けませんと言われた。
I was told the damage is so severe it's beyond repair.
3A polite prohibition meaning 'must not do' or 'you shouldn't do that.'
ここで遊んでは行けません。
You must not play here.
試験中にカンニングをしてはいけません、と注意されたが行けませんという強い言い方だった。
I was warned that cheating during the exam is forbidden; '行けません' was used firmly.
4The negative of 'to go' — 'cannot go' (unable to attend or go somewhere).
申し訳ないですが、明日の会議には行けません。
I'm sorry, but I can't attend tomorrow's meeting.
台風で電車が止まり、予定の場所に行けませんでした。
The trains stopped because of the typhoon and I couldn't get to the place as planned.