put ideas in(to) (one's) head

To suggest something to one; to lead one 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 one's own, especially those that are foolish or negative. Of course we're not going to sell the house! Who's been putting 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.

Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.