cradle-robber
From Longman Dictionary of Contemporary Englishcradle-robberˈcradle-ˌrobber (also cradle-snatcher British English) noun [countable] RELATIONSHIPsomeone who has a romantic relationship with someone who is much younger – used to show disapproval → sugar daddy, toy boy —cradle-rob (also cradle-snatch British English) verb [intransitive]Examples from the Corpuscradle-robber• Traci called Lee Ann a tramp and a cradle-robber.