go soft in the head
go soft in the head
To become dumb, foolish, or witless. You sold the car and bought a scooter? Have you gone soft in the head? Tommy's a good kid, but I think he's gone a little soft in the head.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
be/go soft in the ˈhead
(informal, disapproving) be/become crazy or stupid: Sometimes I talk to myself in the street; people must think I’m soft in the head.Farlex Partner Idioms Dictionary © Farlex 2017