Endlessly daubs pot with reddish-brown (6)
I believe the answer is:
auburn
'reddish-brown' is the definition.
(synonyms)
'endlessly daubs pot' is the wordplay.
'endlessly' indicates the central letters (the ends of the words are removed).
'pot' becomes 'urn' (urn is a kind of pot).
The middle letters of 'daubs' are 'aub'.
'aub'+'urn'='AUBURN'
'with' acts as a link.
(Other definitions for auburn that I've seen before include "Shade of hair" , "Name of Goldsmith's deserted village (6)" , "Shade of brown" , "Of hair colour, reddish brown (6)" , "Red-brown hair colouring" .)