One who takes off in a hurry (8)
I believe the answer is:
streaker
'one who takes off in a hurry' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is all the clue.
Can you help me to learn more?
(Other definitions for streaker that I've seen before include "Rat reeks (anag.)" , "One barely running in public" , "A naughtily nude runner (8)." , "One running out of clothes?" , "Exhibitionist spectator" .)