Answer: iamnot

AnswerCrossword Clue
IAMNOT

Thin defense against the charge that "you're a nerd!"

IAMNOT

"... a crook!"

IAMNOT

Retort to "You are too!"

IAMNOT
Lead-in for a crook?
IAMNOT
"You are, too!" preceder
IAMNOTResponse to "You are so"
IAMNOTAnswer to an accusation, maybe
IAMNOT"You are so!" response
IAMNOTDefinitive disclaimer
IAMNOTKid's rebuttal
IAMNOT"You are too" response
IAMNOT"Yes, you are!" retort
IAMNOTRetort to "You are a liar!"
IAMNOT"You are so!" preceder
IAMNOTResponse to an accusation
IAMNOTIndignant denial