Learner's definition of MAD
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]
— see also fighting mad at 1fight
2 a : having or showing severe mental illness : insane
b : unable to think in a clear or sensible way c : very foolish
(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.
3 chiefly British, informal : liking someone or something very much : very fond of or enthusiastic about someone or something — often + about 4 always used before a noun : wild and uncontrolled
drive (someone) mad
1 : to cause (someone) to become mentally ill 2 : to annoy or bother (someone) very much.
1 : to become mentally ill 2 : to act in a way that is out of control : to act wildly
1 : with a lot of energy and speed