The Collaborative International Dictionary of English v.0.48:

Assent \As*sent"\, n. [OE. assent, fr. assentir. See Assent,
   v.]
   The act of assenting; the act of the mind in admitting or
   agreeing to anything; concurrence with approval; consent;
   agreement; acquiescence.
   [1913 Webster]

         Faith is the assent to any proposition, on the credit
         of the proposer.                         --Locke.
   [1913 Webster]

         The assent, if not the approbation, of the prince.
                                                  --Prescott.
   [1913 Webster]

         Too many people read this ribaldry with assent and
         admiration.                              --Macaulay.
   [1913 Webster]

   Royal assent, in England, the assent of the sovereign to a
      bill which has passed both houses of Parliament, after
      which it becomes law.
      [1913 Webster]

   Syn: Concurrence; acquiescence; approval; accord.

   Usage: Assent, Consent. Assent is an act of the
          understanding, consent of the will or feelings. We
          assent to the views of others when our minds come to
          the same conclusion with theirs as to what is true,
          right, or admissible. We consent when there is such a
          concurrence of our will with their desires and wishes
          that we decide to comply with their requests. The king
          of England gives his assent, not his consent, to acts
          of Parliament, because, in theory at least, he is not
          governed by personal feelings or choice, but by a
          deliberate, judgment as to the common good. We also
          use assent in cases where a proposal is made which
          involves but little interest or feeling. A lady may
          assent to a gentleman's opening the window; but if he
          offers himself in marriage, he must wait for her
          consent.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Assent \As*sent"\, v. t. [imp. & p. p. Assented; p. pr. & vb.
   n. Assenting.] [F. assentir, L. assentire, assentiri; ad +
   sentire to feel, think. See Sense.]
   To admit a thing as true; to express one's agreement,
   acquiescence, concurrence, or concession.
   [1913 Webster]

         Who informed the governor . . . And the Jews also
         assented, saying that these things were so. --Acts
                                                  xxiv. 9.
   [1913 Webster]

         The princess assented to all that was suggested.
                                                  --Macaulay.
   [1913 Webster]

   Syn: To yield; agree; acquiesce; concede; concur.
        [1913 Webster]

WordNet (r) 3.0 (2006):

assent
    n 1: agreement with a statement or proposal to do something; "he
         gave his assent eagerly"; "a murmur of acquiescence from
         the assembly" [syn: assent, acquiescence]
    v 1: to agree or express agreement; "The Maestro assented to the
         request for an encore" [syn: assent, accede,
         acquiesce] [ant: dissent]

Moby Thesaurus II by Grady Ward, 1.0:

187 Moby Thesaurus words for "assent":
   OK, abide by, accede, accede to, accept, acceptance, acclaim,
   accord, accord to, accordance, acquiesce, acquiesce in,
   acquiescence, affinity, affirmation, affirmative,
   affirmative voice, agree, agree to, agree with, agreement,
   answer to, applaud, approbation, approval, approve, approve of,
   assort with, aye, be agreeable, be consistent, be of one,
   be uniform with, be willing, blessing, buy, check, cheer, chime,
   chorus, cohere, coherence, coincide, coincidence, compatibility,
   complaisance, compliance, comply, concert, concord, concordance,
   concur, condescend, conform, conform with, conformance,
   conformation, conformity, congeniality, congruence, congruency,
   congruity, connivance, connive at, consent, consent to silently,
   consist with, consistency, consonance, consort, cooperate,
   cooperation, correspond, correspondence, deference, deign,
   dovetail, eagerness, endorse, endorsement, equivalence,
   face the music, fall in together, fit together, give consent,
   give the nod, go along with, go together, go with, grant, hail,
   hang together, harmonize, harmony, have no objection, hit,
   hold together, hold with, homage, in toto, interlock, intersect,
   intersection, jibe, kneeling, knock under, knuckle down,
   knuckle under, live with it, lock, match, nod, nod assent,
   nonopposal, nonopposition, nonresistance, not refuse, not resist,
   obedience, obeisance, obey, okay, oneness, overlap, parallel,
   parallelism, passiveness, passivity, peace, permission, permit,
   promptitude, promptness, rapport, ratification, ratify, readiness,
   receive, register, register with, relent, resign, resignation,
   resignedness, respond to, sanction, say aye, say yes,
   self-consistency, sing in chorus, sort with, square, square with,
   stand together, subjection, submission, submit, submittal,
   subscribe to, succumb, supineness, swallow it, swallow the pill,
   symmetry, sync, synchronism, take, take it, take kindly to, tally,
   timing, ungrudgingness, uniformity, union, unison, unisonance,
   unloathness, unreluctance, vote affirmatively, vote aye, vote for,
   welcome, willingness, wink at, yes, yield assent, yielding



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

ASSENT, contracts. An agreement to something that has been done before.
     2. It is either express, where it is openly declared; or implied, where
it is presumed by law. For instance, when a conveyance is made to a man, his
assent to it is presumed, for the following reasons; cause there is a strong
intendment of law, that it is for a person's benefit to take, and no man can
be supposed to be unwilling to do that which is for his advantage. 2.
Because it would seem incongruous and absurd, that when a conveyance is
completely executed on the part of the grantor, the estate should continue
in him. 3. Because it is contrary to the policy of law to permit the
freehold to remain in suspense and uncertainty. 2 Ventr. 201; 3 Mod. 296A 3
Lev. 284; Show. P. C. 150; 3 Barn. & Alders. 31; 1 Binn. R. 502; 2 Hayw.
234; 12 Mass IR. 461 4 Day, 395; 5 S. & R. 523 20 John. R. 184; 14 S. & R.
296 15 Wend. R. 656; 4 Halst. R. 161; 6 Verm. R. 411.
     3. When a devise draws after it no charge or risk of loss, and is,
therefore, a mere bounty, the assent of the devisee to, take it will be
presumed. 17 Mass. 73, 4. A dissent properly expressed would prevent the
title from passing from the grantor unto the grantee. 1 2 Mass. R. 46 1. See
3 Munf. R. 345; 4 Munf. R. 332, pl. 9 5 Serg. & Rawle, 523; 8 Watts, R. 9,
11 20 Johns. R. 184. The rule requiring an express dissent, does not apply,
however, when the grantee is bound to pay a consideration for the thing
granted. 1 Wash. C. C. Rep. 70.
     4. When an offer to do a thing has been made, it is not binding on the
party making it, until the assent of the other party has been given and such
assent must be to the same subject-matter, in the same sense. 1 Summ. 218.
When such assent is given, before the offer is withdrawn, the contract is
complete. 6 Wend. 103. See 5 Wend. 523; 5 Greenl. R. 419; 3 Mass. 1; 8 S. R.
243; 12 John. 190; 19 John. 205; 4 Call, R. 379 1 Fairf. 185; and Offer.
     5. In general, when an assignment is made to one for the benefit of
creditors the assent of the assignees will be presumed. 1 Binn. 502, 518; 6
W. & S. 339; 8 Leigh, R. 272, 281. But see 24 Wend. 280.