CHIP ON (ONE’S) SHOULDER, CLAM UP, CLEAN SLATE [WIPE THE SLATE CLEAN]: American English Idioms #41
CHIP ON (ONE’S) SHOULDER A chip on one’s shoulder is an expression for perceived or imaginary insult, often seen as the result of a person’s own insecurity. The term comes from the military metaphor meaning to carry (and protect) one’s weapon (the shoulder) higher than usual because of the feeling that one needs to be…