not know what to make of (someone or something)
To not be sure of what one thinks about someone or something; to not have a clear or confident impression or understanding of someone or something. I came into the interview wearing a full clown costume with makeup, and I could tell they didn't know what to make of me at all. We're receiving a message from the alien spacecraft, but I don't know what to make of their language.
not know what to make of someone or something
not to understand someone or something; not to be able to interpret something or the actions of someone. We really don't know what to make of his request.