inbetweener

noun

1. A person who specializes in tweening in an animation studio.
2. A person who or thing that falls between different groups or characteristics.

   “More than an outsider he was an in-betweener; caught between two cultures all the while shunning his own.”

   “But having two bikes works well for me—so well that I'm daydreaming about getting a third, an in-betweener, light and strong enough to carry me over mountains with a sleeping bag and tent on the back.”

   “Now, Barney was what some voices referred to as an “inbetweener.” It met that he was never located in a permanent grade level. Back in those days when a student was found unfit of advancing to a higher level, he was held back for only half of the year and then advanced for the other half.”