1. cause somebody to learn, understand, or accept something
Professional
Social
he/she just can't seem to get it through his/her head
The expression to get through to someone or to get something through somebody's head refers to making someone understand what you are trying to say or to accept what you are telling them, usually when they are reluctant to believe you or they refuse to face facts. This is an informal expression usually used in social contexts and cant be quite aggressive or rude as it is a strong phrase.