password (also watchword)

n secret word or phrase used by sb to indicate to sb else (eg a sentry) that he is a friend rather than an enemy 口令: give the password 答口令.

passer-by, passerby, passim, passing, passion, Passion Sunday, Passion Week, passion-flower, passion-fruit, passion-play, passionate, passionately, passive, passive resistance, passively, passivity, passkey, Passover, passport, password, past, past question, past-due, pasta, paste, paste-up, pasteboard, pastel, pastern, pasteurization, pasteurisation, pasteurize, pasteurise, pastiche, pastille, pastime, pasting, pastor, pastoral, pastrami, pastry, pastry-cook,