Almost too iron-plated? Wrong (5)
I believe the answer is:
false
'wrong' is the definition.
(similar in meaning)
'almost too iron-plated?' is the wordplay.
'almost' means to remove the last letter (almost the whole word is kept).
'too' becomes 'also' (synonyms).
'iron' becomes 'fe' (chemical symbol for iron).
'plated?' means one lot of letters goes inside another (plated can mean covered or coated).
'also' with its last letter taken off is 'als'.
'als' inserted within 'fe' is 'FALSE'.
(Other definitions for false that I've seen before include "Forged" , "Sham" , "Not genuine or real" , "Spurious, untrue" , "Unfaithful" .)