Wiktionary
square peg into a round hole
alt. (rfc-def) (context idiomatic English) Something or someone that does not fit well or at all; something that will not succeed as attempted, except possibly with much force and effort. n. (rfc-def) (context idiomatic English) Something or someone that does not fit well or at all; something that will not succeed as attempted, except possibly with much force and effort.