Self-censor

Children haven't learned how to self-censor, and are likely to say very inappropriate things at very inappropriate times.

We all self-censor, often without even realising it, that is, we tailor our words and actions to suit the occasion.

The harassment can lead journalists to self-censor, remove themselves from online platforms, sometimes permanently, or even lead to women quitting journalism altogether.

There's been a lot of talk recently about the problem of "libel chill" on British science writing, that people self-censor for fear they'd be sued (as Simon Singh was by British Chiropractic Association).

An antimeme is an idea with self-censoring properties; an idea which, by its intrinsic nature, discourages or prevents people from spreading it.