The Collaborative International Dictionary of English v.0.48:

Theft \Theft\ (th[e^]ft), n. [OE. thefte, AS.
   [thorn]i['e]f[eth]e, [thorn][=y]f[eth]e, [thorn]e['o]f[eth]e.
   See Thief.]
   1. (Law) The act of stealing; specifically, the felonious
      taking and removing of personal property, with an intent
      to deprive the rightful owner of the same; larceny.
      [1913 Webster]

   Note: To constitute theft there must be a taking without the
         owner's consent, and it must be unlawful or felonious;
         every part of the property stolen must be removed,
         however slightly, from its former position; and it must
         be, at least momentarily, in the complete possession of
         the thief. See Larceny, and the Note under Robbery.
         [1913 Webster]

   2. The thing stolen. [R.]
      [1913 Webster]

            If the theft be certainly found in his hand alive, .
            . . he shall restore double.          --Ex. xxii. 4.
      [1913 Webster]

WordNet (r) 3.0 (2006):

theft
    n 1: the act of taking something from someone unlawfully; "the
         thieving is awful at Kennedy International" [syn:
         larceny, theft, thievery, thieving, stealing]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "theft":
   acquisition, appropriation, boosting, burglary, caper, claiming,
   embezzlement, filch, filching, grab, heist, hijacking, job,
   larceny, lift, lifting, pilferage, pilfering, pinch, pinching,
   possession, purloining, reception, rip-off, robbery, robbing,
   score, shoplifting, snitching, steal, stealage, stealing, swiping,
   taking, taking away, taking possession, thievery, thieving,
   touch



Easton's 1897 Bible Dictionary:

Theft
   Punished by restitution, the proportions of which are noted in 2
   Sam. 12:6. If the thief could not pay the fine, he was to be
   sold to a Hebrew master till he could pay (Ex. 22:1-4). A
   night-thief might be smitten till he died, and there would be no
   blood-guiltiness for him (22:2). A man-stealer was to be put to
   death (21:16). All theft is forbidden (Ex. 20:15; 21:16; Lev.
   19:11; Deut. 5:19; 24:7; Ps. 50:18; Zech. 5:3; Matt. 19:18; Rom.
   13:9; Eph. 4:28; 1 Pet. 4:15).


Bouvier's Law Dictionary, Revised 6th Ed (1856):

THEFT, crimes. This word is sometimes used as synonymous with larceny,
(q.v.) but it is not so technical. Ayliffe's Pand. 581 2 Swift's Dig. 309.
     2. In the Scotch law, this is a proper and technical word, and
signifies the secret and felonious abstraction of the property of another
for sake of lucre, without his consent. Alison, Princ. Cr. Law of Scotl.
250.