henchman

Concise Oxford English Dictionary © 2008 Oxford University Press:
henchman/ˈhentʃmən/

▶noun (pl. henchmen)

• 1 chiefly derogatory a faithful follower or political supporter, especially one prepared to engage in crime or dishonest practices.

• 2 historical a squire or page of honour to a person of rank.

  ■ (in Scotland) the principal attendant of a Highland chief.

– origin ME, from OE hengest ‘male horse’ + man, the original sense being prob. ‘groom’.