about-turn

 
(also chiefly North American about-face)
British

noun

  • (chiefly in military contexts) a turn made so as to face the opposite direction: he did an about-turn and marched out of the tent
  • a complete change of opinion or policy: the government made an about-turn over the bill

verb

[no object]
  • turn so as to face the opposite direction: suddenly he about-turned and saluted again

exclamation

(about turn!)
  • a military command to make an about-turn.

Origin:

late 19th century (originally as a military command): shortening of right about turn