Nag me to get heavyweight (7)
I believe the answer is:
megaton
'heavyweight' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'nag me to' is the wordplay.
'nag me to' can be anagrammed to 'MEGATON'.
Though, I am not clear how this is indicated.
'get' acts as a link.
Can you help me to learn more?
(Other definitions for megaton that I've seen before include "Powerful explosive unit" , "Explosive power equivalent to one million tons of TNT" , "Measure of explosive power - montage (anag)" , "weight" , "it weighs a lot" .)