Popular attempt to follow Latin argot (5)
I believe the answer is:
lingo
'argot' is the definition.
('lingo' can be a synonym of 'argot')
'popular attempt to follow latin' is the wordplay.
'popular' becomes 'in'.
'attempt' becomes 'go' (go is a kind of attempt).
'to follow' is a charade indicator (letters next to each other).
'latin' becomes 'l'.
'in'+'go'='ingo'
'ingo' put after 'l' is 'LINGO'.
(Other definitions for lingo that I've seen before include "special words" , "speech" , "means to communicate" , "Language (informally)" , "French?" .)