Wise Men can entertain one wizard (8)
I believe the answer is:
magician
'wizard' is the definition.
(I know that wizard can be written as magician)
'wise men can entertain one' is the wordplay.
'wise men' becomes 'magi' (the three wise men from the nativity).
'entertain' means one lot of letters goes inside another.
'one' becomes 'I' (Roman numeral).
'can' enclosing 'i' is 'cian'.
'magi'+'cian'='MAGICIAN'
(Other definitions for magician that I've seen before include "Conjurer, illusionist" , "Wizard like cartoon Mandrake" , "Conjuror or sorcerer" , "Conjuror, illusionist" , "One working wonders" .)