Dude

Dude was a word which the Twelfth Doctor introduced "several centuries early" in 12th century Essex. (TV: The Magician's Apprentice)

Jack Harkness once called the Sixth Doctor "dude". (AUDIO: Piece of Mind)

The Thirteenth Doctor once called Jack Robertson "dude", proclaiming "I call people dude now." (TV: Arachnids in the UK)