turn ‧ a ‧ bout /ˈtɜːnəbaʊt $ ˈtɜːrn-/ BrE AmE noun
1 . [countable usually singular] British English a complete change in someone’s opinions, ideas, or methods:
an extraordinarily rapid turnabout in attitudes
2 . turnabout is fair play American English used to say that because someone else has done something to you, you can do it to them too