adjective
madder; maddest
not used before a noun chiefly US informal :very angry
having or showing severe mental illness :insane
unable to think in a clear or sensible way
very foolish
chiefly Brit informal :liking someone or something very much :very fond of or enthusiastic about someone or something
always used before a noun :wild and uncontrolled
drive (someone) mad
to cause (someone) to become mentally ill
to annoy or bother (someone) very much.
go mad
to become mentally ill
to act in a way that is out of control :to act wildly
like mad
informal
with a lot of energy and speed
very quickly
very much
mad as a hatter