Give them all you’ve got; strike the final blow. This expression dates from Mark Twain’s day, and indeed he used it in A Connecticut Yankee in King Arthur’s Court (1889). The Yankee (narrator) is describing an argument over comparative prices and salary and says, “I prepared, now, to sock it to him. I said: ‘Look here, dear friend, what’s become of your high wages you were bragging about?’” Although old, the term did not gain wide currency until the 1960s, when a version of it appeared on a popular television show, Rowan and Martin’s Laugh-In. Put as sock it to me!, it apparently came from jazz slang and meant “liven things up.” The speaker then encountered a bucket of water over the head, a blow, or some similar attack. Incidentally, the colloquial verb to sock, meaning to strike, dates from about 1700, and its ultimate origin has been lost.