Craven Cottage finally fills lowly ground (6)
I believe the answer is:
yellow
'craven' is the definition.
(thesaurus)
'cottage finally fills lowly ground' is the wordplay.
'finally' indicates one should take the final letters.
'fills' is an insertion indicator.
'ground' indicates an anagram ('grind' the letters into a new form).
The last letter of 'cottage' is 'e'.
'lowly' anagrammed gives 'yllow'.
'e' placed inside 'yllow' is 'YELLOW'.
(Other definitions for yellow that I've seen before include "Offensively sensational" , "Custardy shade" , "'Caution' colour" , "All looks it to the jaundiced eye" , "likely to run" .)