Spoil appearance of a little devil? (6)

I believe the answer is:
impair
'spoil' is the definition.
(synonyms)
'appearance of a little devil?' is the wordplay.
I cannot really understand how this works, but
'appearance' could be 'air' (both can mean an impression or character) and 'air' is found within the answer.
'devil?' could be 'imp' (devilish creature) and 'imp' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for impair that I've seen before include "Cause weakening of, damage" , "Spoil, degrade" , "Damage or injure" , "Damage or handicap" , "Hobble" .)
