One who is accident free? (7)
I believe the answer is:
planner
'one who is accident free?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'one' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for planner that I've seen before include "Appointment diary" , "One making proposal" , "diary, perhaps" , "Whole-year calendar" , "Council worker" .)