The colour of poor Horace suffering a loss (5)
I believe the answer is:
ochre
'the colour' is the definition.
(ochre is a kind of colour)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for ochre that I've seen before include "paint type" , "Earth-coloured pigment" , "Gold coins, perhaps" , "Red or yellow pigment" , "Brown" .)