1. noun
a) Someone who engages in rubbernecking, or turning and staring.
"A suitable washer B1 and rubberneck B2, both of well known description, are provided to form with clapper arm B3 a watertight joint..."
"Hi, rubberneck! he clutched at her pear-like breast jutting from her sweater — how long did you think youll duck me?"
2. verb
To watch by craning the neck (as though it were made of rubber), especially if the observer and observed are in motion relative to each other.
The driver was so busy rubbernecking, trying to get a good view of the accident, that he was almost part of another accident.
Wikipedia foundation.