Lawgiver's original weight (6)
I believe the answer is:
newton
'lawgiver's' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'original weight' is the wordplay.
'original' becomes 'new' (similar in meaning).
'weight' becomes 'ton' (unit of weight).
'new'+'ton'='NEWTON'
Can you help me to learn more?
(Other definitions for newton that I've seen before include "Thandie - - , actress" , "Explainer of gravity" , "Famous mathematician" , "Isaac . . . . . ., great English physicist who discovered gravity" , "He is said to have discovered gravity" .)