Very eager to be changing colour, say (5)
I believe the answer is:
dying
This could be a double definition.
'very eager' is the first definition.
'dying' can be an answer for 'eager' (I've seen this in another clue). I am not certain of the 'very' bit.
'changing colour say' is the second definition.
'dying' can be an answer for 'changing' (dying is a kind of changing). I'm not certain of the 'colour say' bit.
'to be' acts as a link.
Can you help me to learn more?
(Other definitions for dying that I've seen before include "Expiring" , "Perishing" , "On one's last legs" , "Coluring, hair or fabric" , "Starting to stop!" .)