Recommend an expert with posture (7)
I believe the answer is:
propose
'recommend' is the definition.
(thesaurus)
'an expert with posture' is the wordplay.
'an expert' becomes 'pro' (short for professional).
'with' says to put letters next to each other.
'posture' becomes 'pose' (synonyms).
'pro'+'pose'='PROPOSE'
(Other definitions for propose that I've seen before include "advance" , "Tender" , "Present for consideration" , "Suggest - make an offer" , "Put forward (motion)" .)