1) Sleeper 2) Sleepwalker 3) Slumberer 4) Somnambulist 1) Sleepwalker 2) Somnambulist 
• (n.) A somnambulist. • (n.) A somnambulist.
Noc·tam'bu·list noun A somnambulist. 
noctambulist Someone who walks around in his or her sleep.noctambulator, noctambulist Someone who primarily walks, or eats, or performs other motor activities while asleep at night and which the person does not remember having done after waking up.