STFU HEFTER Share definition Flag A member of the STFU family. Can be used to emphatically exclaim to your d0nk or n00b friend that you really want them to shut the fuck up. "STFU HEFTER, stop being a d0nk." "OMG AYFKM?" STFU HEFTER!" STFU HEFTER by Mr. Pahncake January 14, 2008 Get the STFU HEFTER mug.