Project ending in failure — might sacking come from that? (4)
I believe the answer is:
jute
'might sacking come from that?' is the definition.
'project ending in failure' is the wordplay.
'project' becomes 'jut' (I've seen this in another clue).
'ending in' suggests the final letters.
The final letter of 'failure' is 'e'.
'jut'+'e'='JUTE'
(Other definitions for jute that I've seen before include "Coarse fibre used in making sacks etc" , "Fibre used for ropes and sacks" , "fibrous plant" , "Fibre for hessian etc" , "Rough rope fibre" .)