Cuckold

This is an unsatisfactory word, since it applies not to one who has cuckolded somebody else, but to one who was passively cuckolded. I think the verb is at fault, not the noun—why not use cuckoldise, or cuckoldate?

You might say that there is a parallel case in dupe: a dupe is someone who's duped just as a cuckold is someone who's cuckolded. (Like cuckold, dupe derives from a French word for a bird, in this case the hoopoe.)

French troops in the first world war used to impress the British by singing a popular song the chorus of which contained the assertion: "Il est cocu, le chef de gare". Sadly, I have been unable to discover the rest of this interesting story about the infidelity of the stationmaster's wife.

The French word occurs again in one of Georges Brassens' songs, Le Mauvais Sujet Repenti, in which a rotten salaud has acquired une maladie honteuse from the girlfriend who provides him with his income, and:
Après des injections aiguës d'antiseptique,
J'abandonnai l'métier d'cocu systématique.

I do not know whether this rather witty description of a pimp's function is widely used, or whether Brassens coined it*.

[My Harrap gives bastard, bugger, sod or louse for an English salaud (I suppose rotter is only in Wodehouse nowadays), but in Swedish he's a lortgris or a snuskpelle, and in Dutch a stinker. Just thought I'd mention it.]

*[Céline has kindly resolved this doubt for me: see comment below.]