Fair to be arranged with sign outside (3,3)
I believe the answer is:
not bad
'fair' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for not bad that I've seen before include "Fairly good, all things considered" , "Quite good" , "Grudging praise" , "could be OK" , "Passable" .)