mad

don't get mad, get even used to advise in favour of revenge rather than fruitless rage. informal

☞ This expression was a saying popularized by the US president John F. Kennedy, who called it 'that wonderful law of the Boston Irish political jungle'.

1998New Scientist The Wellcome Trust doesn't get mad, it gets even.

like mad with great intensity, energy, or enthusiasm. informal

2013Mac Observer The bloggers at CNET were freaking out …, the audience was cheering like mad, and a Rush fan site has already picked up on it.

mad as a box of frogs wildly eccentric or crazy. informal

2018Sarah LangfordIn Your Defence Look, you'll see in evidence, but my client is as mad as a box of frogs, and somehow he's slipped it past both doctors.

mad as a hatter (or a March hare) completely crazy. informal

☞ In this expression, a hatter refers to Lewis Carroll's character, the Mad Hatter, in Alice's Adventures in Wonderland (1865). It is thought that hatters suffered from the effects of mercury poisoning because of the fumes arising from the use of mercurous nitrate in the manufacture of felt hats. The March hare version refers to the way hares leap about during the breeding season.

mad as a (cut) snake crazy or eccentric. Australian informal