Get the better of some, without doubt (5)
I believe the answer is:
outdo
'get the better of' is the definition.
(thesaurus)
'some without doubt' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'OUTDO' is hidden within 'without doubt'.
(Other definitions for outdo that I've seen before include "Exceed" , "Perform better than another" , "going to top?" , "Defeat" , "Surpass, go one better than" .)