Colour of object choked by seaweed (8)
I believe the answer is:
lavender
'colour' is the definition.
(I know that lavender is a colour)
'object choked by seaweed' is the wordplay.
'object' becomes 'end' (both can mean a goal or purpose).
'choked by' indicates putting letters inside (I've seen this in other clues).
'seaweed' becomes 'laver' (I have seen 'Edible seaweed ' mean 'laver' so perhaps 'seaweed' could also mean 'laver').
'end' going into 'laver' is 'LAVENDER'.
'of' acts as a link.
(Other definitions for lavender that I've seen before include "Pale lilac" , "bloomer" , "Shrub with fragrant purple flowers, used to scent linen" , "Pale bluish-purple" , "shade" .)