my bad

my bad

That was my mistake; I admit that that was my fault. Primarily heard in US. Susan: "Jerry, I asked you to do the dishes an hour ago, and they're still piled in the sink!" Jerry: "Oops, my bad, honey. I'll do them right now."
See also: bad
Farlex Dictionary of Idioms.

my bad

VERY INFORMAL
People say my bad to mean that something is their fault. Whoops! Sorry dudes! My bad!
See also: bad
Collins COBUILD Idioms Dictionary, 3rd ed.

my bad

used to acknowledge responsibility for a mistake. North American informal
See also: bad
Farlex Partner Idioms Dictionary

ˈmy bad

(American English, informal) used when you are admitting that something is your fault or that you have made a mistake: I’m sorry — my bad. No, it’s my bad. I’m the one that got caught taking stuff.
See also: bad
Farlex Partner Idioms Dictionary

My bad

phr. It’s my fault and I’m sorry. My bad. It won’t happen again.
See also: bad
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

my bad

Slang
Used to acknowledge that one is at fault.
See also: bad
American Heritage® Dictionary of the English Language, Fifth Edition.

mea culpa

It’s my fault, my mistake. The term was taken over from Latin as far back as the 1200s and continues to be used in this way. Ian Rankin had it in Strip Jack (1992), “‘You haven’t had a proper lock fitted yet.’ ‘Mea culpa, Inspector. Fear not, one’s on its way.’” A newer slangy version of this ancient Latin expression is my bad, only a few decades old but ubiquitous enough to be considered a cliché. Novelist John Lescroart used it in The Hunt Club (2009): “‘Yeah, you’re right, I’m sorry. My bad.’ Juhle hung his head.”
The Dictionary of Clichés by Christine Ammer
See also:
  • (one) can't be arsed
  • can't be arsed
  • pile on
  • pile on(to)
  • acknowledge the corn
  • beam in (one's) eye
  • a beam in your eye
  • a bone of contention
  • bone of contention
  • contention