square peg in a round hole

noun1

1. •
   Someone or something that does not fit well or at all in a certain setting; a misfit; hence, someone or something that will not succeed in an endeavour, except possibly with much effort and force.

   • It is almost as if you have guidelines for putting a square peg into a square hole, but we are trying to apply those same guidelines to put a square peg into a round hole. — 1985