Colours fade (4)
I believe the answer is:
flag
I believe this is a double definition.
'colours' is the first definition.
(colour can mean a national flag)
'fade' is the second definition.
(I've seen this before)
(Other definitions for flag that I've seen before include "Droop; iris" , "variety of plant" , "National standard" , "Get weary" , "what Amundsen planted" .)