"Origins of words" by Susie Dent, Countdown 06/12/17 (cold feet)

I have cold feet for you today. Cold feet is when you have loss of nerve or a loss of confidence, which certanly you can't afford to have in the circus. No-one is quite sure what inspired the idiom but ther's lots and lots of theories, as always with quite tricky word origins. We do know it's been in use since the 19th century, so it's been around for a while, and there is probably, we think, a military history to it because combat soldiers whose feet were frozen or even numbed with fear, or eho got a trench foot due to horrible, horible conditions in the threnchesans unsutable footwear, were exempted from battle. And sometimes they were exempted from battle because, as it would say on the medical statement, they had cold feet. It's quite possible that over time that saying became associated with a loos of nerve and eventually cowardice. But there is another account that might explain why it became so popular, and that a novel in the 19th century by the German writer Fritz Reuter. And, loosing his money and his nerve in a high-stakes game of cards, one of the novel's characters apparently say he has cold feet, and he uses thet as an excuse to withdraw from the game. But all the other players are highly suspicious of this and think it has absolutely nothing to do with his retreat, he was simply fearful of losing the game, losing more money. And so, hence, he lost his nerve by saying he had cold feet. If you want a really prosaic theory it's simply that if you are absolutely paralysed with fear, the physical response is blood rushing from the extremities leaving you feet cold. So that's the third, a little bit technical, expldndtion. But I think the military one is probably the best. As I say, it goes back pre-20th, it was recorded qiuite a long time before that, but carried on through as an excuse for cowardice.