1. (n.) An officer who supplies the place of a superior in his absence; a representative of, or substitute for, another in the performance of any duty.

2. (n.) A commissioned officer in the army, next below a captain.

3. (n.) A commissioned officer in the British navy, in rank next below a commander.

4. (n.) A commissioned officer in the United States navy, in rank next below a lieutenant commander.

ADC CO G-man MP OD acolyte adjutant admiral advocate agent aid aide aide-de-camp aider alter ego alternate amicus curiae assistant attendant attorney auxiliary backup backup man bailiff beadle beagle best man bound bailiff brigadier brigadier general captain catchpole champion chicken colonel chief of police chief of staff chief petty officer coadjutant coadjutor coadjutress coadjutrix colonel commandant commander commander in chief commanding officer commissioned officer commissioner commodore company officer constable deputy deputy sheriff detective dummy ensign exec executive officer exponent fed federal field marshal field officer figurehead first lieutenant five-star general fleet admiral flic four-star general gendarme general general officer generalissimo government man help helper helpmate helpmeet inspector jemadar junior officer lictor lieutenant colonel lieutenant commander lieutenant general lieutenant junior grade locum locum tenens mace-bearer major major general marechal marshal mounted policeman narc naval officer navarch officer one-star general orderly officer paranymph paraprofessional patrolman peace officer petty officer pinch hitter pleader police captain police commissioner police constable police inspector police matron police officer police sergeant policeman policewoman portreeve procurator proxy rear admiral reeve representative risaldar roundsman second second in command secondary senior officer sergeant sergeant at arms servant shavetail sheriff sideman sirdar skipper staff officer stand-in subahdar subaltern sublieutenant substitute superintendent supporting actor supporting instrumentalist surrogate the Old Man the brass three-star general tipstaff tipstaves top brass trooper two-star general understudy utility man vicar vicar general vice vice admiral vicegerent warrant officer