Consul's certificate on top of table (8)
I believe the answer is:
diplomat
'consul's' is the definition.
(thesaurus)
'certificate on top of table' is the wordplay.
'certificate' becomes 'diploma' (diploma is a kind of certificate).
'on top of' suggests taking the first letters (I've seen 'on top' mean this).
The initial letter of 'table' is 't'.
'diploma'+'t'='DIPLOMAT'
(Other definitions for diplomat that I've seen before include "Official engaged in international negotiations" , "negotiator" , "Limp toad (anag.)" , "tactful one" , "Overseas representative" .)