Flower is given behind their backs (4)
I believe the answer is:
iris
'flower' is the definition.
(iris is a type of flower)
'is given behind their backs' is the wordplay.
'given' is a charade indicator (letters next to each other).
'behind' becomes 'i' (I can't explain this - if you can you should believe this answer much more).
'backs' says to take the final letters (I've seen 'back' mean this).
The final letter of 'their' is 'r'.
'i'+'r'='ir'
'is' after 'ir' is 'IRIS'.
Can you help me to learn more?
(Other definitions for iris that I've seen before include "Film about writer _______ Murdoch" , "Flowers in the eye?" , "Woman" , "Camera diaphragm" , "is 21[WOMAN], perhaps" .)