Thief, n.; pl. Thieves.
Etymology: [OE. thef, theef, AS. ; akin to OFries. thiaf, OS. theof, thiof, D. dief, G. dieb, OHG. diob, Icel. , Sw. tjuf, Dan. tyv, Goth. , , and perhaps to Lith. tupeti to squat or crouch down. Cf. Theft.]
1. One who steals; one who commits theft or larceny. See Theft. There came a privy thief, men clepeth death. Chaucer. Where thieves break through and steal. Matt. vi. 19.
2. A waster in the snuff of a candle. Bp. Hall. Thief catcher. Same as Thief taker. -- Thief leader, one who leads or takes away a thief. L'Estrange. -- Thief taker, one whose business is to find and capture thieves and bring them to justice. -- Thief tube, a tube for withdrawing a sample of a liquid from a cask. -- Thieves' vinegar, a kind of aromatic vinegar for the sick room, taking its name from the story that thieves, by using it, were enabled to plunder, with impunity to health, in the great plague at London. [Eng.]
Syn. -- Robber; pilferer. -- Thief, Robber. A thief takes our property by stealth; a robber attacks us openly, and strips us by main force. Take heed, have open eye, for thieves do foot by night. Shak. Some roving robber calling to his fellows. Milton.
Shades of meaning
Fernald has no entry of its own for thief; he lists it under robber.
Where he writes about it:
A robber seeks to obtain the property of others by force or intimidation; a thief by stealth and secrecy. — from robber
In early English thief was freely used in both senses, as in Shakespeare and the Authorized Version of the English Bible, which has "two thieves" (Matt. xxvii, 38), where the Revised Version more correctly substitutes "two robbers." — from robber