Prince maybe offensive to describe colour (5,4)
I believe the answer is:
royal blue
'colour' is the definition.
(royal blue is a kind of colour)
'prince maybe offensive to describe' is the wordplay.
I cannot quite see how this works, but
'prince' could be 'royal' (prince is a type of royal) and 'royal' is found within the answer.
The remaining letters 'blue' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for royal blue that I've seen before include "Bally euro (anag.)" , "Dark colour" , "A shade Conservative" , "Deep rich shade of colour" , "(Regal?) colour" .)