See, having an eye for language (6)
I believe the answer is:
coptic
'language' is the definition.
(Coptic is an example)
'see having an eye' is the wordplay.
'see' becomes 'c' (the word for the letter, according to Chambers).
'having' is a charade indicator (letters next to each other).
'an eye' becomes 'optic' ('optic' can be a synonym of 'eye').
'c'+'optic'='COPTIC'
'for' is the link.
(Other definitions for coptic that I've seen before include "A language of Egypt" , "Egyptians in the past" , "Egyptian Christian church" , "Ancient church language" , "Sweet; fungus" .)