The Collaborative International Dictionary of English v.0.48:

Enjoin \En*join"\, v. t. [imp. & p. p. Enjoined; p. pr. & vb.
   n. Enjoining.] [F. enjoindre, L. injungere to join into,
   charge, enjoin; in + jungere to join. See Join, and cf.
   Injunction.]
   1. To lay upon, as an order or command; to give an injunction
      to; to direct with authority; to order; to charge.
      [1913 Webster]

            High matter thou enjoin'st me.        --Milton.
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            I am enjoined by oath to observe three things.
                                                  --Shak.
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   2. (Law) To prohibit or restrain by a judicial order or
      decree; to put an injunction on.
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            This is a suit to enjoin the defendants from
            disturbing the plaintiffs.            --Kent.
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   Note: Enjoin has the force of pressing admonition with
         authority; as, a parent enjoins on his children the
         duty of obedience. But it has also the sense of
         command; as, the duties enjoined by God in the moral
         law. "This word is more authoritative than direct, and
         less imperious than command." --Johnson.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Enjoin \En*join"\, v. t.
   To join or unite. [Obs.] --Hooker.
   [1913 Webster]

WordNet (r) 3.0 (2006):

enjoin
    v 1: issue an injunction
    2: give instructions to or direct somebody to do something with
       authority; "I said to him to go home"; "She ordered him to do
       the shopping"; "The mother told the child to get dressed"
       [syn: order, tell, enjoin, say]

Moby Thesaurus II by Grady Ward, 1.0:

160 Moby Thesaurus words for "enjoin":
   adjure, admonish, advise, appreciate, arrest, ban, bar, bid, boast,
   bridle, burden with, call on, call the signals, call upon, caution,
   charge, check, command, commission, constrain, contain, control,
   cool, cool off, cotton to, counsel, curb, curtail, debar,
   decelerate, declare, decree, delight in, demand, deny, dictate,
   direct, disallow, dompt, dote, drink in, eat up, embargo,
   encourage, enjoy, exact, exclude, exclude from, exhort,
   expostulate, fancy, fasten upon, fill, forbid, forewarn,
   freight with, give an order, give the word, go, govern, guard,
   hinder, hold, hold at bay, hold back, hold fast, hold in,
   hold in check, hold in leash, hold up, impose, impose on,
   impose upon, incite, induce, inflict on, inflict upon, inhibit,
   instruct, interdict, issue a caveat, issue a command, issue a writ,
   keep, keep back, keep from, keep in, keep in check,
   keep under control, lay, lay on, lay under restraint, levy, like,
   love, luxuriate in, maintain, mandate, mind, move, occupy, ordain,
   order, order about, outlaw, own, persuade, place, possess, preach,
   preclude, prescribe, prevent, proclaim, prohibit, prompt,
   promulgate, pronounce, proscribe, pull, pull in, put, put down,
   put on, put upon, refuse, rein, rein in, reject, relish,
   remonstrate, repress, restrain, retain, retard, retrench, rule,
   rule out, saddle with, savor, say no to, say the word, set,
   set back, shut out, slow down, snub, straiten, subject to,
   suppress, taboo, take to, task, tax, tell, urge, warn,
   weight down with, withhold, yoke with