a square peg

a square peg (in a round hole)

someone who is different from most people of the same age and situation In high school she was defininitely a square peg, but even if they didn't understand her, most kids admired her.
See also: peg, square

a square peg (in a round hole)

someone whose character makes them completely wrong for the type of work they are doing or for the situation they are in I never did understand what Paddy was doing in accounts - he was a square peg in a round hole.
See also: peg, square
References in classic literature ?
A square peg forced into a round hole, he had felt like a daily outrage that long established smooth roundness into which a man of less sharply angular shape would have fitted himself, with voluptuous acquiescence, after a shrug or two.
The report explains how the significant changes in the macro environment in recent years have changed key conditions required for hard currency pegs, increasingly making it look like trying to fit a square peg to a round hole.
Manager Terry Robins said: "A square can makes complete sense as our trolleys, baskets, boxes and even our lorries are all square - now we're putting a square peg in a square hole.
Some kids are here because they are a square peg and simply don't fit the hole,'' said Martin, who was assistant principal for 10 years at both Westlake and Thousand Oaks high schools before coming to Conejo Valley five years ago.
In effect, existing methods of signal processing use brute force to jam a square peg into a round hole.