Founder of NSYNC vocalised after Justin finally left (4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

definition: founder as a verb e.g. a ship might founder/sink sounds like (“vocalised”): [ n ]SYNC, with the final letter of [Justi]- n removed for the surface, Justin Timberlake was a part of the boyband NSYNC [wiki]