Fertile area in a desert (5)
I believe the answer is:
oasis
'fertile area in a desert' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for oasis that I've seen before include "Peaceful area away from trouble" , "Fertile patch in a desert" , "place to escape gloom?" , "water you'll want here" , "Fertile place in a desert, a watering hole" .)