Some bozo needing gas (5)
I believe the answer is:
ozone
'gas' is the definition.
(I know that ozone is a type of gas)
'some bozo needing' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'OZONE' can be found hidden inside 'bozo needing'.
(Other definitions for ozone that I've seen before include "Kind of oxygen layer in atmosphere, has hole in it" , "It's said to brace" , "Toxic form of oxygen" , "That precious layer" , "Sea air; bleaching agent" .)