British "bye-bye"

TATA

Think of how a child might wave off a London bus cheerfully in two quick syllables.

"British 'bye-bye'" refers to the informal British slang "tata," which is a playful way to say goodbye. It mimics the sound of a child’s farewell and is commonly used in the UK, much like "bye-bye" in other English dialects. The clue plays on the cultural difference, swapping a familiar phrase for its British equivalent.