ADJECTIVE (3)

1. intended or adapted to afford protection of some kind;
- Example: "a protective covering"
- Example: "the use of protective masks and equipment"
- Example: "protective coatings"
- Example: "kept the drunken sailor in protective custody"
- Example: "animals with protective coloring"
- Example: "protective tariffs"

2. showing care;
- Example: "a protective mother"

3. (usually followed by `of') solicitously caring or mindful;
- Example: "protective of his reputation"

The Collaborative International Dictionary of English v.0.48:

Protective \Pro*tect"ive\, a. [Cf. F. protectif.]
   Affording protection; sheltering; defensive. " The favor of a
   protective Providence." --Feltham.
   [1913 Webster]

   Protective coloring (Zool.), coloring which serves for the
      concealment and preservation of a living organism. Cf.
      Mimicry. --Wallace.

   Protective tariff (Polit. Econ.), a tariff designed to
      secure protection (see Protection, 4.), as distinguished
      from a tariff designed to raise revenue. See Tariff, and
      Protection, 4.
      [1913 Webster]

WordNet (r) 3.0 (2006):

protective
    adj 1: intended or adapted to afford protection of some kind; "a
           protective covering"; "the use of protective masks and
           equipment"; "protective coatings"; "kept the drunken
           sailor in protective custody"; "animals with protective
           coloring"; "protective tariffs" [ant: unprotective]
    2: showing care; "a protective mother"
    3: (usually followed by `of') solicitously caring or mindful;
       "protective of his reputation"

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "protective":
   careful, conservational, conservationist, conservative,
   conservatory, conserving, covering, custodial, defending,
   defensive, fostering, guardian, guarding, heedful, immunizing,
   jealous, keeping, parental, possessive, preservative, preservatory,
   preserving, preventative, preventive, prophylactic, protecting,
   safeguarding, saving, screening, self-defensive, self-preservative,
   self-protective, sheltering, shielding, tutelary, vigilant,
   watchful