hook [OE] Hooks have many uses: for catching hold of things, for hanging things on, for controlling sheep, for carrying bait, and others. The angler’s hook features in hook, line, and sinker [M19th], used to emphasize that someone has been completely deceived or tricked. The items all form part of fishing tackle, where a sinker is a weight used to sink the fishing line in the water. The image behind the expression is of a hungry fish deceived by the bait into gulping everything down. The expression off the hook [M19th], ‘no longer in trouble or difficulty’, is almost the opposite: the idea here is of a fish managing to wriggle off the hook that lodged in its mouth when it took the bait.

The type of hook referred to in by hook or by crook, ‘by any possible means’, is not certain. The expression goes back to the 14th century and probably comes from farming, with the crook being a shepherd’s hooked staff and the hook a ‘billhook’, a heavy curved pruning knife. How these implements might have been used together comes from the writer and political reformer William Cobbett, who in 1822 described an ancient English forest law. According to this, people living near woodland were allowed to gather dead tree branches for fuel, using the hook to cut them off or the crook to pull them down. To play hooky, or play truant, is a 19th-century US expression. It probably comes from hook off or hook it, meaning ‘to go away’.