put ideas into someone's head(redirected from put an idea in someone's head)
put ideas in(to) (one's) head
To suggest something to someone; to lead someone to start believing (in) something; to make someone want to start doing something. (Used of suggestions, ideas, or beliefs that one wouldn't have thought of on his or her own, especially those that are foolish or negative.) Of course we're not going to sell the house! Who's been putting such ideas in your head? I can't believe you were caught smoking marijuana. I bet it's that no-good kid Casey who put ideas like that into your head. I heard John putting ideas into his sister's head that she was adopted.
put ideas into someone's head
Also, put an idea in someone's head. Suggest something to someone, as in No, we're not moving-what put that idea in your head? [Mid-1800s]