Colour of ogre entrails, to some extent (5)
I believe the answer is:
green
'colour' is the definition.
(greening is a kind of colouring)
'of ogre entrails to some extent' is the wordplay.
'to some extent' indicates a hidden word.
'GREEN' is hidden within 'of ogre entrails'.
(Other definitions for green that I've seen before include "Environment-friendly" , "Unripe; envious" , "Envious; naive" , "It's for putting on - colour - inexperienced" , "political activist" .)