Small number attempt to entertain a public official (6)
I believe the answer is:
notary
'public official' is the definition.
(I've seen this before)
'small number attempt to entertain a' is the wordplay.
'small number' becomes 'no' (abbreviation; 'small' indicates a short form).
'attempt to' becomes 'try' (I've seen this in other clues).
'entertain' means one lot of letters goes inside another.
'try' enclosing 'a' is 'tary'.
'no'+'tary'='NOTARY'
(Other definitions for notary that I've seen before include "Official authorised to witness document signing" , "Legal officer" , "legal worker" , "One drawing up legal documents" , "Official legally authorised to witness signatures" .)