Journalist taken in by posh language (7)
I believe the answer is:
swedish
'language' is the definition.
(Swedish is an example)
'journalist taken in by posh' is the wordplay.
'journalist' becomes 'ed' (short for editor).
'taken in by' is an insertion indicator.
'posh' becomes 'swish' ('swish' can be a synonym of 'posh').
'ed' placed within 'swish' is 'SWEDISH'.
(Other definitions for swedish that I've seen before include "like Bergman" , "Nationality that swished around" , "Like Abba" , "Nordic" , "Soprano Jenny Lind, b. Stockholm 1798, d. Herefordshire 1887" .)