Pretends to be iron sign damaged (6)
I believe the answer is:
feigns
'pretends' is the definition.
('feign' can be a synonym of 'pretend')
'iron sign damaged' is the wordplay.
'iron' becomes 'Fe' (chemical symbol for iron).
'damaged' indicates an anagram.
'sign' with letters rearranged gives 'igns'.
'fe'+'igns'='FEIGNS'
'to be' acts as a link.
(Other definitions for feigns that I've seen before include "Pretends to be affected by" , "Makes a pretence of" , "Pretends, simulates" , "Pretends, creates false appearance" , "Pretends or fabricates" .)