( BrE , informal ) a person who does not feel happy or comfortable in a particular situation, or who is not suitable for it
A SQUARE PEG (IN A ROUND HOLE)
Meaning of A SQUARE PEG (IN A ROUND HOLE) in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005