A woman or man that does not fall into the category as fat or skinny. In other words, the perfect body shape.
List of celebrity examples. Scarlett Johansson, Jennifer Aniston, Jake Ggyllenhaal, Beyonce, Britney Spears, Brad Pitt, Bradley Cooper, Gerard Butler, Reese Witherspoon, Nina Dobrev, Paul Wesley, Ian Somerhalder, and so on and so on.. all are inbetweeny.
1) Damn, that sexy woman is perfectly inbetweeny.
2) Taylor Swift is hot, but I wish she was more inbetweeny.
3) Im looking for a man who isn't too big or too small. Something inbetweeny.