Select new top (3)
I believe the answer is:
opt
'select' is the definition.
(I've seen this before)
'new top' is the wordplay.
'new' indicates an anagram.
'top' is an anagram of 'OPT'.
(Other definitions for opt that I've seen before include "Prefer, choose" , "Decide between possibilities, choose" , "Make a choice" , "Elect" , "Select as a preferable alternative" .)