Scientist gives novel weight (6)
I believe the answer is:
newton
'scientist' is the definition.
(Sir Isaac Newton)
'novel weight' is the wordplay.
'novel' becomes 'new' (novel means new or fresh).
'weight' becomes 'ton' (unit of weight).
'new'+'ton'='NEWTON'
'gives' acts as a link.
(Other definitions for newton that I've seen before include "Supposedly, an apple fell on his head" , "inclined to apply discovery?" , "Polymath who stated the laws of gravity and motion" , "Sir Isaac -, seventeen to eighteenth century English scientist" , "Great English scientist who discovered gravity" .)