Found in the following dictionaries
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
"Tweener" Definition
noun
A computing device that is smaller than a traditional laptop, but larger than a PDA.
Source: Wiktionary
A person who plays at two positions, not good enough at either to be restricted to it.
Source: Wiktionary
A person, machine or piece of software that performs tweening.
Source: Wiktionary
A professional wrestler who is neutral or morally ambiguous; neither a face nor a heel, or showing no favoritism to either allegiance.
Source: Wiktionary
A player who has some but not all of the necessary characteristics for each of two or more positions (as in football or basketball).
Source: Merriam-Webster