A flash flood?
A five-letter word for sudden movement is probably "start." Make sure the "d" is correct.
swell, climb, surge
Crash is a 5-letter word that can refer to "a sudden noise".
fervent
craving
onrush
Sudden
Unexpected
A five letter word for bravery is valor.
A five letter word for a game is "match."
Five letter word for tough:RigidStiffSolidDenseStoutTight