Automatons (6)
'automatons' is the definition.
('zombie' can be a synonym of 'automaton')
This is all the clue.
(Other definitions for zombies that I've seen before include "Mob size (anag.)" , "Voodoo undead" , "Lethargic people" , "Spooky beings" , "those who find it impossible to sleep" .)
'automatons' is the definition.
('robot' can be a synonym of 'automaton')
This is the entire clue.
(Other definitions for robots that I've seen before include "Mechanisms that can move automatically" , "Automata" , "Mechanical men" , "Automatons, machines or sci-fi creatures" , "Automatons, programmed machines" .)