Half a ton (3)
I believe the answer is:
kip
'half a ton' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for kip that I've seen before include "Sleep, nap (colloq.)" , "Nap (slang)" , "Snooze" , "Sleep (sl.)" , "Short sleep" .)