Nitwit (8)
'nitwit' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for twerp that I've seen before include "Foolish fellow" , "Ninny" , "In slang, a stupid or objectionable person" , "ass" , "Numpty" .)
(Other definitions for booby that I've seen before include "Gannet" , "Pink-footed seabird" , "Dunce" , "Stupid person" , "marine bird" .)
'nitwit' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for bonehead that I've seen before include "Stupid person with ossified cranium" , "stupid leader" , "Numbskull" , "Fool" , "Idiot" .)