madder; maddest
1
not used before a noun chiefly US, informal
: very angry
If you keep teasing that dog, you'll make/get him mad.
She's mad at me. = (less commonly) She's mad with me.
What are you so mad about?
That guy makes me so mad!
She was mad at me for being late. = She was mad that I was late. = She was mad about my being late.
She was hopping mad. [=extremely angry]
2
a
: having or showing severe mental illness : insane
(chiefly Brit) The man in the park was clearly mad.
a movie about a mad scientist
He was stark raving mad. [=completely insane] = (Brit) He was barking mad.
b
: unable to think in a clear or sensible way
He was mad [=insane] with jealousy/anger.
(chiefly Brit) They must have been mad [=crazy] to buy that house.
a power-mad prosecutor
c
: very foolish
(chiefly Brit) He made a mad decision to drive home in the storm.
3
chiefly British, informal
: liking someone or something very much : very fond of or enthusiastic about someone or something
She's mad for a cute boy in her class.
He's mad keen on sailing.
—often + aboutShe's mad [=wild] about dancing.
He's mad [=crazy] about her.
4
always used before a noun
: wild and uncontrolled
There was a mad [=frantic] rush when the store opened.
a mad scramble
Cite this Entry
“Mad.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/mad. Accessed 23 Jun. 2026.
Copy Citation
