The Collaborative International Dictionary of English v.0.48:

fealty \fe"al*ty\ (f[=e]"al*t[y^]), n. [OE. feaute, OF.
   feaut['e], fealt['e], feelt['e], feelteit, fr. L. fidelitas,
   fr. fidelis faithful. See Feal, and cf. Fidelity.]
   1. Fidelity to one's lord; the feudal obligation by which the
      tenant or vassal was bound to be faithful to his lord; the
      special oath by which this obligation was assumed;
      fidelity to a superior power, or to a government;
      loyality. It is no longer the practice to exact the
      performance of fealty, as a feudal obligation. --Wharton
      (Law Dict.). --Tomlins.
      [1913 Webster]

   2. Fidelity; constancy; faithfulness, as of a friend to a
      friend, or of a wife to her husband.
      [1913 Webster]

            He should maintain fealty to God.     --I. Taylor.
      [1913 Webster]

            Makes wicked lightnings of her eyes, and saps
            The fealty of our friends.            --tennyson.
      [1913 Webster]

            Swore fealty to the new government.   --Macaulay.
      [1913 Webster]

   Note: Fealty is distinguished from homage, which is an
         acknowledgment of tenure, while fealty implies an oath.
         See Homage. --Wharton.

   Syn: Homage; loyality; fidelity; constancy.
        [1913 Webster]

WordNet (r) 3.0 (2006):

fealty
    n 1: the loyalty that citizens owe to their country (or subjects
         to their sovereign) [syn: allegiance, fealty]

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "fealty":
   acquiescence, adherence, adhesion, allegiance, ardor,
   assigned task, attachment, bona fides, bond, bonne foi,
   bounden duty, burden, business, call of duty, charge, commitment,
   compliance, conformity, constancy, dedication, deference,
   dependability, devoir, devotedness, devotion, duteousness,
   duties and responsibilities, dutifulness, duty, ethics, faith,
   faithfulness, fidelity, firmness, good faith, homage, imperative,
   line of duty, loyalty, mission, must, obedience, obediency,
   obligation, observance, onus, ought, piety, place, reliability,
   respect, self-imposed duty, service, servility, servitium,
   staunchness, steadfastness, submission, submissiveness,
   suit and service, suit service, support, tie, troth, true blue,
   trueness, trustworthiness, truth, willingness



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

FEALTY. Fidelity, allegiance.
     2. Under the feudal system, every owner of lands held them of some
superior lord, from whom or from whose ancestors, the tenant had received
them. By this connexion the lord became bound to protect the tenant in the
enjoyment of the land granted to him; and, on the other hand, the tenant was
bound to be faithful to his lord,, and defend him against all his enemies.
This obligation was called fidelitas, or fealty. 1 Bl. Com. 366; 2 Bl. Com.
86; Co. Litt. 67, b; 2 Bouv. Inst. n. 1566.