( informal ) to be sensitive about sth that happened in the past and become easily offended if it is mentioned because you think that you were treated unfairly
HAVE A CHIP ON YOUR SHOULDER (ABOUT STH)
Meaning of HAVE A CHIP ON YOUR SHOULDER (ABOUT STH) in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005