A spot of refreshment (5)
I believe the answer is:
oasis
'a spot' is the definition.
(I have seen 'Fertile spot' mean 'oasis' so perhaps 'spot' could also mean 'oasis')
'of refreshment' is the wordplay.
'of' becomes 'o''.
'refreshment' becomes 'asis' (I can't justify this - if you can you should give a lot more credence to this answer).
'o'+'asis'='OASIS'
Can you help me to learn more?
(Other definitions for oasis that I've seen before include "Q-and-A game" , "Fertile area in desert" , "Fertile place like waterhole in desert" , "Spring of fresh water in a desert" , "Desert pool" .)