ADJECTIVE (3)

1. susceptible to attack;
- Example: "a vulnerable bridge"

2. susceptible to criticism or persuasion or temptation;
- Example: "vulnerable to bribery"
- Example: "an argument vulnerable to refutation"

3. capable of being wounded or hurt;
- Example: "vulnerable parts of the body"

The Collaborative International Dictionary of English v.0.48:

Vulnerable \Vul"ner*a*ble\, a. [L. vulnerabilis wounding,
   injurious, from vulnerare to wound, vulnus a wound; akin to
   Skr. vra?a: cf. F. vuln['e]rable.]
   [1913 Webster]
   1. Capable of being wounded; susceptible of wounds or
      external injuries; as, a vulnerable body.
      [1913 Webster]

            Achilles was vulnerable in his heel; and there will
            be wanting a Paris to infix the dart. --Dr. T.
                                                  Dwight.
      [1913 Webster]

   2. Liable to injury; subject to be affected injuriously;
      assailable; as, a vulnerable reputation.
      [1913 Webster]

            His skill in finding out the vulnerable parts of
            strong minds was consummate.          --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vulnerable
    adj 1: susceptible to attack; "a vulnerable bridge" [ant:
           invulnerable]
    2: susceptible to criticism or persuasion or temptation;
       "vulnerable to bribery"; "an argument vulnerable to
       refutation"
    3: capable of being wounded or hurt; "vulnerable parts of the
       body"

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "vulnerable":
   aidless, answerable for, apt to, assailable, attackable, beatable,
   breakable, brittle, brittle as glass, capable of, conquerable,
   crackable, crisp, crispy, crumbly, crushable, defenseless,
   delicate, dependent on, exposed to, expugnable, fatherless,
   fissile, flimsy, fracturable, fragile, frail, frangible, friable,
   friendless, guideless, helpless, in danger of, incident to,
   lacerable, leaderless, liable to, likely to, motherless, naked to,
   obliged to, open to, penetrable, pregnable, prone to, ready for,
   responsible for, scissile, shatterable, shattery, shivery,
   splintery, standing to, subject to, surmountable, susceptive to,
   unfriended, unprotected, untenable, vincible, weak,
   within range of