Informed the first ex (4)
I believe the answer is:
told
'informed' is the definition.
(telling is a kind of informing)
'the first ex' is the wordplay.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'first ex' becomes 'old' (I can't explain this - if you can you should believe this answer much more).
't'+'old'='TOLD'
Can you help me to learn more?
(Other definitions for told that I've seen before include "Authorised - broadcast" , "Said" , "Produced effect; related" , "Made an impact" , "instructed" .)