Source : Webster's Revised Unabridged Dictionary (1913)

Guardian \Guard"i*an\, a.
   Performing, or appropriate to, the office of a protector; as,
   a guardian care.

   {Feast of Guardian Angels} (R. C. Ch.) a church festival
      instituted by Pope Paul V., and celebrated on October 2d.
      

   {Guardian angel}.
   (a) The particular spiritual being believed in some branches
       of the Christian church to have guardianship and
       protection of each human being from birth.
   (b) Hence, a protector or defender in general. --O. W.
       Holmes.

   {Guardian spirit}, in the belief of many pagan nations, a
      spirit, often of a deceased relative or friend, that
      presides over the interests of a household, a city, or a
      region.

Guardian \Guard"i*an\, n. [OF. guardain, gardien, F. gardien,
   LL. guardianus. See {Guard}, v. t., and cf. {Wasden}.]
   1. One who guards, preserves, or secures; one to whom any
      person or thing is committed for protection, security, or
      preservation from injury; a warden.

   2. (Law) One who has, or is entitled to, the custody of the
      person or property of an infant, a minor without living
      parents, or a person incapable of managing his own
      affairs.

            Of the several species of guardians, the first are
            guardians by nature. -- viz., the father and (in
            some cases) the mother of the child.  --Blockstone.

   {Guardian ad litem}(Law), a guardian appointed by a court of
      justice to conduct a particular suit.

   {Guardians of the poor}, the members of a board appointed or
      elected to care for the relief of the poor within a
      township, or district.

Source : WordNet®

guardian
     adj : providing protective supervision; watching over or
           safeguarding; "daycare that is educational and not just
           custodial"; "a guardian angel"; "tutelary gods" [syn: {custodial},
            {tutelary}, {tutelar}]

guardian
     n : a person who cares for persons or property [syn: {defender},
          {protector}, {shielder}]