I can't find a translation for 'turnabout' in the standard Esperanto sources, and Google Translate throws up its hands at it.
Google Translate is not a good source to check. I would recommend the annotated dictionary at esperanto.me. For "Turn about is fair play" it lists ĉiu laŭ sia vico. For other meanings of "turnabout", I would suggest using a thesaurus and checking those words in the annotated dictionary.