A flower almost deep blue (4)
I believe the answer is:
anil
'deep blue' is the definition.
(blue dye and its specific colour)
'a flower almost' is the wordplay.
'flower' becomes 'nile' (Nile is an example).
'almost' means to remove the last letter (most of the word but not all of it).
'nile' with its final letter taken off is 'nil'.
'a'+'nil'='ANIL'
(Other definitions for anil that I've seen before include "Indian man" , "Species of blue" , "West Indian shrub, source of indigo" , "name of man" , "It produces dye" .)