m-word

The word motherfucker, regarded as a vulgar word.

Any word beginning with m that is not normally taboo but is considered (often humorously) to be so in the given context, like midget or murder.

Alternative letter-case form of m-word.

Given all this, you may be puzzled to hear me call myself a Marxist. […] This is not something that I often volunteer to talk about in “polite society” because the very mention of the M-word switches audiences off.