have a down on (someone or something)
To have or express negative or overly critical feelings toward someone or something. I don't know why you have a down on Robert—he's such a nice guy to everyone! Don't have a down on this vacation to your grandparents' farm. I know it's not very exotic, but we'll still have a great time!
have a down on someone/something
or have a downer on someone/something
BRITISHIf you have a down on someone or something or you have a downer on them, you do not like them or you disapprove of them. Snobs would have a down on a man with a south London accent. For some reason Jackie has always had a downer on me.
have a (or be) down on
disapprove of; feel hostile or antagonistic towards. informal