big deal

WordReference Random House Learner's Dictionary of American English © 2026

ˈbig ˈdeal, n. [countable] Informal.

1. Slang Terms something or someone important or impressive:
   I'm only a few minutes late; what's the big deal?

interj. 

2. Slang Terms (used to show that one considers something to be unimportant or not impressive): So you're the mayor's cousin — big deal!

WordReference Random House Unabridged Dictionary of American English © 2026

big′ deal′, [Slang.]

1. Slang Terms an important or impressive person or thing:
   to make a big deal out of nothing; I hear he's a big deal on Wall Street now.
2. Slang Terms (used ironically as an interjection to indicate that one considers something to be unimportant or unimpressive):
   So you're the mayor's cousin —big deal!

• 1945–50

Collins Concise English Dictionary © HarperCollins Publishers::

big deal interjection

1. an exclamation of scorn, derision, etc, used esp to belittle a claim or offer