Verbal dig between partners (6)
I believe the answer is:
spoken
'verbal' is the definition.
(similar in meaning)
'dig between partners' is the wordplay.
'dig' becomes 'poke' (synonyms).
'between' is an insertion indicator.
'partners' becomes 'sn' (South and North are partners in the game bridge).
'poke' going within 'sn' is 'SPOKEN'.
(Other definitions for spoken that I've seen before include "Uttered through the medium of speech" , "Said" , "Oral" , "Verbalised" , "Voiced" .)