Go in for what may be graphic language (5)
I believe the answer is:
argot
'graphic language' is the definition.
'argot' can be an answer for 'language' (argot can mean jargon or slang). I am not certain of the 'graphic' bit.
'go in for what' is the wordplay.
'in for' indicates putting letters inside.
'what' becomes 'art' (I can't justify this - if you can you should give a lot more credence to this answer).
'go' inserted inside 'art' is 'ARGOT'.
'may be' is the link.
Can you help me to learn more?
(Other definitions for argot that I've seen before include "Language of a particular group" , "Specialised language" , "Groat (anag)" , "Special jargon of a group" , "Patois, vernacular" .)