Fairy has limitless aura (3)
I believe the answer is:
air
This clue might be a double definition.
'fairy' is the first definition.
(thesaurus)
'limitless aura' is the second definition.
'air' can be an answer for 'aura' (synonyms). I'm not certain of the 'limitless' bit.
'has' is the link.
Can you help me to learn more?
(Other definitions for air that I've seen before include "Tune (on the G string?)" , "Display" , "- brick; - bed; - brush" , "Lay" , "Dry; tune" .)