Gas wizard living here is single (5)
I believe the answer is:
ozone
'gas' is the definition.
(I know that ozone is a type of gas)
'wizard living here is single' is the wordplay.
'wizard living here' becomes 'oz' (I can't justify this - if you can you should believe this answer much more).
'is single' becomes 'one' (a single thing - only one).
'oz'+'one'='OZONE'
Can you help me to learn more?
(Other definitions for ozone that I've seen before include "Pungent form of oxygen" , "A poisonous gas; seaside air" , "Fresh, bracing sea air" , "Gas forming protective layer" , "Gas forming screen against ultraviolet radiation in the stratosphere" .)