Filed from 4 published puzzles

DONTMAKEMELAUGH

Set to 4 different clues across 4 published puzzles, most often "You can't be serious!" — The New York Times, Friday, 12 September 2003.

15 letters

Every clue on record, most used first

"You can't be serious!"once
The New York Times — Friday, 12 September 2003
"Pshaw!"once
The New York Times — Monday, 28 July 2003
Incredulous responseonce
The New York Times — Thursday, 20 June 2002
"Ha!"once
The New York Times — Monday, 14 October 1996

Other answers to these clues

AREYOUKIDDINGME15 letters
HOO3 letters
IBET4 letters
THATSRIDICULOUS15 letters
YOUMUSTBEJOKING15 letters