The colour of one wild dingo! (6)
I believe the answer is:
indigo
'the colour' is the definition.
(indigo is a kind of colour)
'one wild dingo' is the wordplay.
'one' becomes 'i' (Roman numeral).
'wild' is an anagram indicator.
'dingo' with letters rearranged gives 'ndigo'.
'i'+'ndigo'='INDIGO'
'of' is the link.
(Other definitions for indigo that I've seen before include "Deep-blue dye or colour" , "Ellington's Mood" , "Blue/violet dye" , "One of the colours of the rainbow" , "Spectral colour" .)