Cowardice

Cowardice was a trait associated with fear. One who displayed cowardice was refered to as a coward.

Just prior to the Battle of the Game Station. Jack Harkness told the Ninth Doctor that he wished he had never met him, claiming that he was much better off as a coward.

Daring the Doctor to use a delta wave generator to wipe out his Dalek Fleet at the cost of all life on Earth, the Dalek Emperor asked him "What are you, coward or killer?" At the last moment, the Doctor relented using the delta wave, naming himself "coward. Any day." (TV: The Parting of the Ways)

Even at gunpoint, correctly predicted that the Tenth Doctor could not kill him, branding him a coward. (TV: The End of Time)

The Eleventh Doctor made an observation to Gibbis, a native of Tivoli, regarding the cowardice of his people. "Your cowardice isn't quaint, it's sly, aggressive. It's how that gene of gutlessness has survived while so many others have perished."

- The Eleventh Doctor.