(archaic) off with someone's head

(figuratively) to keep a cool head

(figuratively) to hold one's head high, to stand tall

(informal) to get a big head, to become big-headed

(informal) (transitive with de) to make fun of, to laugh at, to take the piss out of

(informal, figuratively) to rack one's brain, to cudgel one's brain

(informal) to have one's wits about one, to have all one's marbles, to be all there

Synonym of prendre la grosse tête

(idiomatic, figurative) nonsensical

headfirst, headlong