Strange giant sure to produce autograph (9)
I believe the answer is:
signature
'autograph' is the definition.
(I've seen this before)
'strange giant sure' is the wordplay.
'strange' indicates an anagram.
'giant'+'sure'='giantsure'
'giantsure' anagrammed gives 'SIGNATURE'.
'to produce' acts as a link.
(Other definitions for signature that I've seen before include "ending to letter?" , "X-WORD ?" , "Personal mark" , "time indicated by this?" , "Autograph" .)