悪怯れる[warubireru] to be timid
怯える[obieru] to become frightened
怯む[hirumu] to falter
卑怯[hikyou] cowardice
卑怯者[hikyoumono] coward

怯懦[kyouda] cowardice
卑怯千万[hikyousenban] very mean (sneaky)
怯え[obie] being startled, surprised or afraid
怯弱[kyoujaku] coward