Airy-fairy? (5)
I believe the answer is:
sylph
'airy-fairy?' is the definition.
(a sylph is an imaginary spirit of the air)
This is all the clue.
(Other definitions for sylph that I've seen before include "Graceful lass" , "Girl with slender figure" , "slender lass!" , "Imaginary (female) being" , "Slim female" .)