I am trying to say that he is neither small nor big but just the one word. He is big. He is small I am not sure now about this He is medium. is not right as a a three word sentence. As opposed to She is small She is petite She is big as in she is tall not big as in fat. Big is an annoying word because it can mean all sorts.
He is average could be one possibility. Thanks! But doesn't that also mean not very bright? His height/buit/physique I need to describe..that is the thing.
No. It just means that they are no smarter/taller and no dumber/shorter than most people. (That's the 'popular' definition - when speaking in strict statistical terms, it's a bit different, but this will suffice for the purpose.)
How about these: 'Indistinctive height' or 'his height was sub-par with his exceptionally tall mates'
By size, I'll assume you mean height, not bulk or some other dimension. In other words, just relate height to that of other characters. The same can be done for other meanings of size. Even if you don't know how tall Sami or Kevin are, you know Sami is the shortest, Kevin the tallest, and Mark is somewhere in between.
