ADJECTIVE (4)

1. filled with fear or apprehension;
- Example: "afraid even to turn his head"
- Example: "suddenly looked afraid"
- Example: "afraid for his life"
- Example: "afraid of snakes"
- Example: "afraid to ask questions"

2. filled with regret or concern; used often to soften an unpleasant statement;
- Example: "I'm afraid I won't be able to come"
- Example: "he was afraid he would have to let her go"
- Example: "I'm afraid you're wrong"

3. feeling worry or concern or insecurity;
- Example: "She was afraid that I might be embarrassed"
- Example: "terribly afraid of offending someone"
- Example: "I am afraid we have witnessed only the first phase of the conflict"

4. having feelings of aversion or unwillingness;
- Example: "afraid of hard work"
- Example: "afraid to show emotion"

The Collaborative International Dictionary of English v.0.48:

Afraid \A*fraid"\, p. a. [OE. afrayed, affraide, p. p. of
   afraien to affray. See Affray, and cf. Afeard.]
   Impressed with fear or apprehension; in fear; apprehensive.
   [Afraid comes after the noun it limits.] "Back they recoiled,
   afraid." --Milton.
   [1913 Webster]

   Note: This word expresses a less degree of fear than
         terrified or frightened. It is followed by of before
         the object of fear, or by the infinitive, or by a
         dependent clause; as, to be afraid of death. "I am
         afraid to die." "I am afraid he will chastise me." "Be
         not afraid that I your hand should take." --Shak. I am
         afraid is sometimes used colloquially to soften a
         statement; as, I am afraid I can not help you in this
         matter.
         [1913 Webster]

   Syn: Fearful; timid; timorous; alarmed; anxious.
        [1913 Webster]

WordNet (r) 3.0 (2006):

afraid
    adj 1: filled with fear or apprehension; "afraid even to turn
           his head"; "suddenly looked afraid"; "afraid for his
           life"; "afraid of snakes"; "afraid to ask questions"
           [ant: fearless, unafraid(p)]
    2: filled with regret or concern; used often to soften an
       unpleasant statement; "I'm afraid I won't be able to come";
       "he was afraid he would have to let her go"; "I'm afraid
       you're wrong"
    3: feeling worry or concern or insecurity; "She was afraid that
       I might be embarrassed"; "terribly afraid of offending
       someone"; "I am afraid we have witnessed only the first phase
       of the conflict"
    4: having feelings of aversion or unwillingness; "afraid of hard
       work"; "afraid to show emotion"

Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "afraid":
   abulic, afeared, aghast, anxious, apologetic, apprehensive, averse,
   backward, cautious, chary, chicken, chickenhearted, coward,
   cowardly, cowed, craven, daunted, dismayed, edgy, faint,
   fainthearted, fear-struck, feared, fearful, feeble, feebleminded,
   frail, frightened, fritter, funking, funky, haunted with fear,
   henhearted, hesitant, indisposed, infirm, intimidated,
   invertebrate, jittery, jumpy, lily-livered, loath, milk-livered,
   milksoppish, milksoppy, mousy, nervous, on edge, overtimid,
   overtimorous, panic-prone, panic-stricken, panicky, pigeonhearted,
   pliable, pusillanimous, rabbity, regretful, reluctant, rueful,
   scared, scared to death, scary, shrinking, shy, sissified, sissy,
   skittish, soft, sorry, spineless, spooked, terrified, timid,
   timorous, uneager, unhappy, unmanly, unmanned, unwilling, wary,
   weak, weak-kneed, weak-minded, weak-willed, weakhearted,
   white-livered, yellow