Fibre for making sails (5)
I believe the answer is:
sisal
'fibre' is the definition.
(sisal is a kind of fibre)
'making sails' is the wordplay.
'making' indicates anagramming the letters.
'sails' with letters rearranged gives 'SISAL'.
'for' acts as a link.
(Other definitions for sisal that I've seen before include "Natural fibre" , "Fibre from agave plant" , "Sails (anag) - fibre" , "Strong rope fibre" , "Type of fibre" .)