freefall

Short definition from Wiktionary

Noun

1. 1
   A state of motion affected by no acceleration or force other than that of gravity.
2. 2
   As above, but allowing for the presence of incidental air resistance not caused intentionally by devices like parachutes or wings.
3. 3
   The state of worsening out of control.

Verb

1. 1
   To drop in a state of freefall.