Some massive twerp (3)
I believe the answer is:
ass
'some massive twerp' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'some massive twerp' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'ASS' is hidden in the letters of 'massive twerp'.
Can you help me to learn more?
(Other definitions for ass that I've seen before include "Foolish person; animal" , "Horse hybrid" , "Jennet" , "Braying animal" , "Wally" .)