Donner le coup de grâce = To give the finishing stroke.
Il gagna mille francs tout d’un coup = He won £40 at one shot, all at once, at one “go.”
Il s’en alla tout à coup = He went away suddenly, abruptly.
[Tout d’un coup and tout à coup are frequently used indiscriminately, even by French people.]
Un coup de tête = A moment of passion; a rash action.
Donner un coup de main = To give a helping hand.
J’ai manqué mon coup = I missed my shot; I failed.
Ils l’ont moulu de coups = They beat him black and blue.
[A well-known quotation from Corneille runs: “Mes pareils à deux fois ne se font pas connaître
Et pour leurs coups d’essai veulent des coups de maître.”—Le Cid, ii. 2.]