All robbers are thieves but only some thieves are robbers.
A thief is anyone who steals something. A robber is someone who steals something under threat of violence. "Your money or your life!" is something said by a robber. Pickpockets, burglars and embezzlers are all thieves. But they are not robbers.
Chief thief is the hinky pink for robber in command.
Thief.
robber
A criminal, a robber, a thief
crook robber, stealer
beef thief
thief, robber, criminal
chief thief
A bandit is a robber, a thief, someone who steals
A leaf thief!!
thief or Tomb rader
highwayman thief raider