hard and fast

Describing a strict rule that cannot be altered under any circumstances. This term originally described a ship that was out of the water, either because it had run aground or because it was in dry dock, and hence could not move. In the mid-nineteenth century the term was trans- ferred to inalterable courses of action or precepts. The OED lists an early figurative use in two different speeches given in the House of Commons in 1867: “The House has . . . determined to have no hard and fast line.”