1. [ verb ] turn, usually 180 degrees
Related terms: turn
2. [ noun ] (military) act of pivoting 180 degrees, especially in a military formation
Synonyms: about_turn
Related terms: reversion
3. [ verb ] change one's mind and assume the opposite viewpoint
Related terms: rethink
4. [ noun ] a reversal in attitude or principle or point of view
Synonyms: reversal policy_change volte-face

: "an about-face on foreign policy"

Related terms: change undoing