Not mad initially, still always near edge (4)
I believe the answer is:
sane
'not mad' is the definition.
(I've seen this in another clue)
'initially still always near edge' is the wordplay.
'initially' suggests taking the first letters.
The initial letters of 'still always near edge' is 'SANE'.
(Other definitions for sane that I've seen before include "Compos mentis" , "Normal" , "Right-minded" , "Reasonable" , "Not mad" .)