1. To do something rebelliously; often disobeying authority or some other source of external social pressure.

2. Common mis-spelling of definitely, often arrived at when a person types definatly or definately into a spell-checker, and the spell-ckecher changes it to "defiantly".
A. Go away you moron!
B. (defiantly) No.

A. Do you want to work 30 hours' unpaid overtime this week?
B. I defiantly don't.
by fwe22 August 28, 2007
A common misspelling of "definitely". Its origin is unknown.
We defiantly need to do that again!
by moosemum August 5, 2012
Jared: I defiantly want to go to the beach today
Edward: You mean definitely?
by ismelllikeawoman17293 July 27, 2020
When peeps try to spell defenetly but FAIL

YOU: defiantly noticed that IRONY
by I am yetched March 31, 2017
to do something in a way that shows a disposition to challenge, resist, or fight.

more often just a misspelling of 'definitely' because the internet is full of dipshits
"She defiantly spoke out against the system."

"Their's defiantly sumthing rong with my phone, it keeps trying to incorektly fix my speling."
by servvo1 December 21, 2021