The Collaborative International Dictionary of English v.0.48:

Relax \Re*lax"\, v. i.
   1. To become lax, weak, or loose; as, to let one's grasp
      relax.
      [1913 Webster]

            His knees relax with toil.            --Pope.
      [1913 Webster]

   2. To abate in severity; to become less rigorous.
      [1913 Webster]

            In others she relaxed again,
            And governed with a looser rein.      --Prior.
      [1913 Webster]

   3. To remit attention or effort; to become less diligent; to
      unbend; as, to relax in study.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Relax \Re*lax"\ (r?-l?ks"), v. t. [imp. & p. p. Relaxed
   (-l?kst"); p. pr. & vb. n. Relaxing.] [L. relaxare; pref.
   re- re- + laxare to loose, to slacken, from laxus loose. See
   Lax, and cf. Relay, n., Release.]
   1. To make lax or loose; to make less close, firm, rigid,
      tense, or the like; to slacken; to loosen; to open; as, to
      relax a rope or cord; to relax the muscles or sinews.
      [1913 Webster]

            Horror . . . all his joints relaxed.  --Milton.
      [1913 Webster]

            Nor served it to relax their serried files.
                                                  --Milton.
      [1913 Webster]

   2. To make less severe or rigorous; to abate the stringency
      of; to remit in respect to strenuousness, earnestness, or
      effort; as, to relax discipline; to relax one's attention
      or endeavors.
      [1913 Webster]

            The statute of mortmain was at several times relaxed
            by the legislature.                   --Swift.
      [1913 Webster]

   3. Hence, to relieve from attention or effort; to ease; to
      recreate; to divert; as, amusement relaxes the mind.
      [1913 Webster]

   4. To relieve from constipation; to loosen; to open; as, an
      aperient relaxes the bowels.
      [1913 Webster]

   Syn: To slacken; loosen; loose; remit; abate; mitigate; ease;
        unbend; divert.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Relax \Re*lax"\, n.
   Relaxation. [Obs.] --Feltham.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Relax \Re**lax"\, a.
   Relaxed; lax; hence, remiss; careless.
   [1913 Webster]

WordNet (r) 3.0 (2006):

relax
    v 1: become less tense, rest, or take one's ease; "He relaxed in
         the hot tub"; "Let's all relax after a hard day's work"
         [syn: relax, loosen up, unbend, unwind,
         decompress, slow down] [ant: tense, tense up]
    2: make less taut; "relax the tension on the rope" [syn:
       relax, unbend]
    3: become loose or looser or less tight; "The noose loosened";
       "the rope relaxed" [syn: loosen, relax, loose] [ant:
       stiffen]
    4: cause to feel relaxed; "A hot bath always relaxes me" [syn:
       relax, unstrain, unlax, loosen up, unwind, make
       relaxed] [ant: strain, tense, tense up]
    5: become less tense, less formal, or less restrained, and
       assume a friendlier manner; "our new colleague relaxed when
       he saw that we were a friendly group" [syn: relax, loosen
       up]
    6: make less severe or strict; "The government relaxed the
       curfew after most of the rebels were caught" [syn: relax,
       loosen]
    7: become less severe or strict; "The rules relaxed after the
       new director arrived" [syn: relax, loosen]
    8: make less active or fast; "He slackened his pace as he got
       tired"; "Don't relax your efforts now" [syn: slack,
       slacken, slack up, relax]