Glib talk by northern model (7)
I believe the answer is:
pattern
'model' is the definition.
(synonyms)
'glib talk by northern' is the wordplay.
'glib talk' becomes 'patter' (I've seen this before).
'by' says to put letters next to each other.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'patter'+'n'='PATTERN'
(Other definitions for pattern that I've seen before include "Repeated decorative design" , "Model or design from which to make clothes, say" , "Shape or design" , "Model to imitate" , "Design for copying" .)