Cowardice was a trait associated with fear. One who displayed cowardice was referred to 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)
Your cowardice isn't quaint, it's sly, aggressive. It's how that gene of gutlessness has survived while so many others have perished.In an alternate timeline in which the Daleks developed the Time Destructor, the First Doctor and Captain Parlos were disgusted by Urbinian Chancellor Atrias' cowardice after he agreed to the Dalek Supreme's demands for surrender and tried to abandon his people to the invaders. The Doctor, who had considered Atrias a friend, correctly predicted that the former Chancellor would get his just desserts. (AUDIO: Daughter of the Gods)