The Collaborative International Dictionary of English v.0.48:

Tutelar \Tu"te*lar\, Tutelary \Tu"te*la*ry\, a. [L. tutelaris:
   cf. F. tut['e]laire. See Tutelage.]
   Having the guardianship or charge of protecting a person or a
   thing; guardian; protecting; as, tutelary goddesses.
   [1913 Webster]

         This, of all advantages, is the greatest . . . the most
         tutelary of morals.                      --Landor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tutelary
    adj 1: providing protective supervision; watching over or
           safeguarding; "daycare that is educational and not just
           custodial"; "a guardian angel"; "tutelary gods" [syn:
           custodial, tutelary, tutelar]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "tutelary":
   ancestral spirits, angel, attendant godling, control, covering,
   custodial, daemon, defensive, demon, fairy godmother, familiar,
   familiar spirit, fostering, genius, genius domus, genius loci,
   good angel, good genius, guardian, guardian angel, guardian spirit,
   guarding, guide, household gods, immunizing, invisible helper,
   lares and penates, lares compitales, lares familiaris,
   lares permarini, lares praestites, lares viales, manes,
   ministering angel, numen, parental, penates, preventive,
   prophylactic, protecting, protective, safeguarding, screening,
   sheltering, shielding, special providence, totem, tutelar god,
   vigilant, watchful