Flower almost at the back (5)
I believe the answer is:
aster
'flower' is the definition.
(aster is a kind of flower)
'almost at the back' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'at the back' becomes 'astern' (I've seen this before).
'astern' with its last letter taken away is 'ASTER'.
(Other definitions for aster that I've seen before include "Daisy-like garden flower" , "Stare oddly at the flower" , "Flower of the daisy family - rates (anag)" , "Flowering plant; tares (anag.)" , "(Starlike) flower" .)