tough [OE] An Old English word related to taut [ME] the early spelling of which was tought. As a noun, meaning ‘a rough and violent man or youth’, it dates from the 1860s, in the USA. If you are as tough as old boots [M19th] you are very sturdy or resilient. The earliest version of the phrase was as tough as leather. Tough love is a US expression dating from the 1960s.