Sailor Brown checked Scottish cloth (6)
I believe the answer is:
tartan
'checked scottish cloth' is the definition.
(checked pattern)
'sailor brown' is the wordplay.
'sailor' becomes 'tar' (tar can mean a sailor).
'brown' becomes 'tan' (tan is a kind of brown).
'tar'+'tan'='TARTAN'
(Other definitions for tartan that I've seen before include "Scots patterned cloth" , "Pattern of the Scottish clans" , "Scottish plaid design" , "Distinctive cloth pattern of a Highlands clan" , "Scots plaid" .)