Shit

In a parallel universe, a Time Lord chided a colleague for his language when he reacted to news of the Doctor's escape with the exclamation "Oh, shit!" (AUDIO: Exile)

Gwen Cooper described a piece of modern art as shit. (AUDIO: More Than This)

Behind the scenes
In COMIC: Assimilation², Jean-Luc Picard and Worf use French and Klingon equivalents of the word "shit", "merde" and "qi'yah" respectively.