The Collaborative International Dictionary of English v.0.48:

Applaud \Ap*plaud"\, v. t. [imp. & p. p. Applauded; p. pr. &
   vb. n. Applauding.] [L. applaudere; ad + plaudere to clash,
   to clap the hands: cf. F. applaudir. Cf. Explode.]
   1. To show approval of by clapping the hands, acclamation, or
      other significant sign.
      [1913 Webster]

            I would applaud thee to the very echo,
            That should applaud again.            --Shak.
      [1913 Webster]

   2. To praise by words; to express approbation of; to commend;
      to approve.
      [1913 Webster]

            By the gods, I do applaud his courage. --Shak.
      [1913 Webster]

   Syn: To praise; extol; commend; cry up; magnify; approve. See
        Praise.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Applaud \Ap*plaud"\, v. i.
   To express approbation loudly or significantly.
   [1913 Webster]

WordNet (r) 3.0 (2006):

applaud
    v 1: clap one's hands or shout after performances to indicate
         approval [syn: applaud, clap, spat, acclaim] [ant:
         boo, hiss]
    2: express approval of; "I applaud your efforts"

Moby Thesaurus II by Grady Ward, 1.0:

58 Moby Thesaurus words for "applaud":
   abide by, accede, accept, acclaim, acquiesce, acquiesce in, agree,
   agree to, agree with, approve, assent, boost, buy, cheer, cheer on,
   clap, clap the hands, commend, compliment, comply, consent, cry,
   cry for joy, encore, eulogize, extol, give a cheer, give a hand,
   give the nod, glorify, hail, hear it for, hold with, hooray,
   hurrah, hurray, huzzah, in toto, laud, magnify, nod, nod assent,
   panegyrize, plug, praise, receive, recommend, root, root for,
   shout, shout hosanna, subscribe to, take kindly to, vote for,
   welcome, yell, yes, yield assent