Duplicate a hundred and fifty-one (5)
I believe the answer is:
clone
'duplicate' is the definition.
(I've seen this in another clue)
'a hundred and fifty-one' is the wordplay.
'a hundred' becomes 'C' (Roman numerals).
'and' is a charade indicator (letters next to each other).
'fifty' becomes 'l' (Roman numeral).
'c'+'l'+'one'='CLONE'
(Other definitions for clone that I've seen before include "Biological replica" , "spit" , "Copied organism" , "Identical copy" , "Plant or animal produced asexually from one parent" .)