F*ck

Fuck was a profane word, sometimes used as a synonym for sex.

The word was used in the expressions "what the fuck?" (TV: Everything Changes, Countrycide) and "fuck knows", (TV: Random Shoes, End of Days) and the terms "fucker" (TV: Countrycide) and "fuck buddy". (TV: Out of Time)

Gwen Cooper once shouted, "Fuck you!" at Jack Harkness after he taunted her for her affair with Owen Harper. (TV: End of Days)

Owen used the word to call a group of cannibals "sick fuckers". (TV: Countrycide)

Rhys Williams once in a fit of rage told Gwen to, "sit the fuck down!" (TV: Combat)

Upon discovering a bomb, Allen Shapiro gave his last words, "Oh, fuck!", immediately before being caught in its explosion. (TV: The Blood Line)