Says who?

Says who?

On whose authority? According to whom? Used to express disagreement with or defiance against something that someone has just said. A: "There's no way a pipsqueak like you can win this race!" B: "Oh yeah? Says who?" A: "You can't take those files to the police!" B: "Oh, really? Says who—you?"
See also: Say
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

Says who?

 and Sez who?
Inf. a formulaic challenge indicating disagreement with someone who has said something. Tom: Says who? Fred: Says me, that's who! She drew herself up to her full height, looked him straight in the eye, and said, "Says who?"
See also: Say
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

says who

Who claims the truth of this statement, which I don't believe? For example, That horse of your will never win a race.-Says who? This slangy expression of disagreement or disbelief may also be put in declarative form, says you!, meaning "I disagree with what you just said." For example, It was an accident, I didn't mean to break it.-Says you! You've always hated that vase . [First half of 1900s]
See also: say, who
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Says who?

and Sez who?
interrog. a formulaic challenge indicating disagreement with someone who has said something. (see also Says you!.) TOM: Says who? FRED: Says me, that’s who! She drew herself up to her full height, looked him straight in the eye, and said, “Says who?”
See also: Say
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
See also: