homing missile

Used to say that someone's mind is elsewhere.

(transitive) to get something into one's head

to cross someone's mind

(informal, figuratively) to go through someone's mind, to go through someone's head, to run through someone's mind, to keep running through someone's mind

(informal) per head, per person

(informal) to have a big head, to be big-headed, to be full of oneself, to be too big for one's britches

(informal, figuratively) to cudgel one's brain, to puzzle over something; to go to a lot of trouble over something

to worry or get obsessed about something

(informal) to be dizzy; to be light-headed