Flower discovered in Fair Isle (4)
I believe the answer is:
iris
'flower' is the definition.
(thesaurus)
'discovered in fair isle' is the wordplay.
'discovered' indicates a hidden word (remove the letters covering the answer in the clue).
'IRIS' is hidden in the letters of 'in fair isle'.
(Other definitions for iris that I've seen before include "Lily" , "Garden flower - part of eye" , "Flag - part of eye" , "Ms Murdoch" , "Coloured eye part" .)