Supporter has faith having lost the second time (5)
I believe the answer is:
truss
'supporter' is the definition.
(type of structural support)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for truss that I've seen before include "Medical support" , "Tie up; support" , "Rusts (anag.)" , "Support - bundle - cluster" , "Surgical appliance" .)