Feel fine about fairy (3)
I believe the answer is:
elf
'fairy' is the definition.
(I know that elf is a type of fairy)
'feel fine about' is the wordplay.
'about' indicates a hidden word (the clue goes around or about the answer).
'ELF' can be found hidden inside 'feel fine'.
(Other definitions for elf that I've seen before include "He causes mischief" , "Mischievous creature" , "Woodland fairy" , "Pixie (able to cobble?)" , "Imaginary small being with magic powers" .)