inbetweenship Share definition Flag the stage between friendship and a relationship. A.K.A. hooking up stage or friends with benefits. sean and aubrey have been in an inbetweenship for almost 3 months now, they need to make it official already inbetweenship by Aaronthethuggg December 21, 2010 0 0 Get merch Get the inbetweenship mug. Buy Now — $32.95 See more merch