Wildly deranged editor missing – have a look! (6)
I believe the answer is:
gander
'look' is the definition.
(informal term for a look or glance)
'wildly deranged editor missing have a' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for gander that I've seen before include "waterbird" , "male member of the Anatidae family" , "Male goose - quick look" , "'What's sauce for the goose is sauce for the . . . . . .'" , "Male bird - look" .)