Green’s Dictionary of Slang

1. (also yucko, yuk) disgusting, repulsive.

1978		S. King Stand (1990) 441: Walso Horton, what a yuck name.
2024		J. Meades Empty Wigs (t/s) 113: Good luck to them. Even if it [i.e. open-air voyeurism] does come on a bit yuck.

2. obscene speech.

2000

Eminem ‘Under the Influence’ 🎵 I got a yuck mouth and it’s polluted.