Consider that "death-defying" is an adjective for a stunt or action that should kill you, but you escape (defy) death.
Deft: skilled in movement, especially of the hands.
Defy: oppose, resist, challenge, or refuse to submit.
You can see why "deft defying" doesn't make much sense. Taken literally, "deft defying" could be used to describe someone that is skilled at opposition or physical resistance, as in "defying deftly".
If hyphenated to become an adjective, "deft-defying" could be used to describe someone either unskilled on purpose, or should be skilled and is not.
"I tried that new masseuse... oh man, her massage was deft-defying. She needs to practice; I was sore for a week."
"Did you catch my deft-defying gaming skills to let my little brother beat me in Mortal Kombat? He doesn't know it, but I like letting him think he won fair and square."
"Did you just call that jump deft defying? Don't you mean death-defying? And it was only off the garage -- you wouldn't die from landing twelve feet, dude. You're an ass."