like mad
very much, very quickly, or with a lot of energy

[TahlilGaran] Dictionary of Contemporary English ▲

like mad
[informal]
if something hurts like mad it hurts very much, and if you do something like mad you do it very quickly and with a lot of force.
This cut stings like mad.

I braked like mad but couldn't stop in time and hit the car in front.

[TahlilGaran] English Idioms Dictionary ▲

like mad
very fast, with great energy
I worked like mad but I was unable to finish the project by noon as I had hoped.

[TahlilGaran] English Idioms Dictionary ▲

like mad
adv., slang, informal With great enthusiasm and vigor; very fast.
We had to drive like mad (like crazy) to get there on time. See: LIKE HELL¹.

[TahlilGaran] English Idioms Dictionary ▲