WordNet (r) 3.0 (2006):

self-effacing
    adj 1: reluctant to draw attention to yourself [syn: reticent,
           self-effacing, retiring]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "self-effacing":
   altruistic, backward, bashful, committed, consecrated, dedicated,
   deprecative, deprecatory, devoted, diffident, disinterested,
   humble, modest, rabbity, retiring, sacrificing, self-abasing,
   self-abnegating, self-abnegatory, self-denying, self-deprecating,
   self-depreciating, self-depreciative, self-devoted,
   self-distrustful, self-doubting, self-forgetful, self-immolating,
   self-neglectful, self-neglecting, self-renouncing,
   self-sacrificing, self-unconscious, selfless, shy, timid,
   unacquisitive, unassertive, unassured, unpossessive, unpretentious,
   unselfconfident, unselfish, unselfreliant, unsparing of self