At one's own instigation, of one's own accord.
off the hook
Performing extraordinarily well.
off the bat
From the start; immediately; right away.
off the wagon
No longer maintaining a program of self-improvement or abstinence from …
off the radar
Unlikely to happen or be important in the near future, or tending to e …
off the deep end
Crazy, erratic, or irrational.
off one's nut
Insane, crazy.