Pants

In the UK, "pants" typically refers to underwear. However, "pants" can also be used as an equivalent of the word "bad", e.g. "That's pants!" Yet another classic British slang term for insult.

Why do the British say pants?

In British English, trousers were already used every day, pantaloons became less known, and the name for the garment worn underneath was shortened from 'underpants' to 'pants'. The term 'pants' is also comedic - one could say 'pants' rather than 'nonsense' or 'rubbish'