Maroon thread (6)
I believe the answer is:
I believe this is a double definition.
'maroon' is the first definition.
(as in stranding or marooning someone somewhere)
'thread' is the second definition.
(strand of material)
(Other definitions for strand that I've seen before include "Leave aground on shore" , "Leave high and dry" , "Beach or shore" , "Beach; London road" , "Drive (ship) aground" .)