Finally achieve a colour like corn (5)
I believe the answer is:
eared
'like corn' is the definition.
(I've seen this in another clue)
'finally achieve a colour' is the wordplay.
'finally' suggests the final letters.
'colour' becomes 'red' (red is a kind of colour).
The final letter of 'achieve' is 'e'.
'e'+'a'+'red'='EARED'
(Other definitions for eared that I've seen before include "Handled" , "like some seals" , "able to listen?" , "Could involving listeners" , "corny?" .)