Girl meeting posh friend every year (8)
I believe the answer is:
annually
'every year' is the definition.
(synonyms)
'girl meeting posh friend' is the wordplay.
'girl' becomes 'ann' (woman's name).
'meeting' is a charade indicator (letters next to each other).
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-U).
'friend' becomes 'ally' (an ally is a friend or supporter).
'ann'+'u'+'ally'='ANNUALLY'
(Other definitions for annually that I've seen before include "as MOTs must be renewed" , "Every year" , "at regular intervals" , "As Christmas is coming" .)