[1] : The Collaborative International Dictionary of English v.0.48

approval \approv"al\, n.
   approbation; sanction.
   1913 webster

         a censor . . . without whose approval n? capital
         sentences are to be executed.            --temple.
   1913 webster

   syn: see approbation.
        1913 webster
see also:
approbation 

[2] : WordNet (r) 2.0

approval
     n 1: the formal act of giving approval; "he gave the project his
          blessing"; "his decision merited the approval of any
          sensible person" syn: blessing, approving ant: disapproval
     2: a feeling of liking something or someone good; "although she
        fussed at them, she secretly viewed all her children with
        approval" ant: disapproval
     3: acceptance as satisfactory; "he bought it on approval" syn:
         favorable reception, favourable reception
     4: a message expressing a favorable opinion; "words of approval
        seldom passed his lips" syn: commendation ant: disapproval
see also:
blessing approving disapproval favorable reception favourable reception commendation 

[3] : Moby Thesaurus II by Grady Ward, 1.0

94 moby thesaurus words for "approval":
   john hancock, ok, acceptance, accord, account, acquiescence,
   admiration, adoration, affirmance, affirmation, affirmative,
   affirmative voice, agreement, apotheosis, applause, appreciation,
   approbation, assent, authentication, authorization, awe, aye,
   blessing, breathless adoration, certification, commendation,
   compliance, compliment, concurrence, confirmation, connivance,
   consent, consideration, countersignature, courtesy, credit,
   deference, deification, duty, eagerness, eclat, endorsement,
   esteem, estimation, exaggerated respect, favor, go-ahead,
   great respect, green light, hero worship, high regard, homage,
   honor, idolatry, idolization, imprimatur, leave, mandate, nod,
   notarization, okay, permission, prestige, promptitude, promptness,
   ratification, readiness, regard, respect, reverence,
   reverential regard, rubber stamp, sanction, seal, sigil, signature,
   signet, stamp, stamp of approval, submission, subscription,
   suffrage, the nod, ungrudgingness, unloathness, unreluctance,
   validation, veneration, visa, vise, warrant, willingness, worship,
   worth

Approval >> A Words
Approval, definition of term: Approval
approval_pag1.html