the act of turning in a different or opposite direction.

a change of opinion, loyalty, etc.

a reciprocal action; act of doing to someone exactly as that person has done to oneself or another

Turnabout is fair play.

a person who changes things; a radical.

Chiefly British . merry-go-round.

noun

changeabout , change of direction , doubleback , flip-flop , reversal , reverse , shift , turnaround , u-turn , volte-face , inversion , transposition