The Collaborative International Dictionary of English v.0.48:

Solicitous \So*lic"it*ous\, a.[L. sollicitus, solicitus. See
   Solicit, v. t.]
   Disposed to solicit; eager to obtain something desirable, or
   to avoid anything evil; concerned; anxious; careful.
   "Solicitous of my reputation." --Dryden. "He was solicitous
   for his advice." --Calerendon.
   [1913 Webster]

         Enjoy the present, whatsoever it be, and be not
         solicitous about the future.             --Jer. Taylor.
   [1913 Webster]

         The colonel had been intent upon other things, and not
         enough solicitous to finish the fortifications.
                                                  --Clarendon.
   [1913 Webster] -- So*lic"it*ous*ly, adv. --
   So*lic"it*ous*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

solicitous
    adj 1: full of anxiety and concern; "solicitous parents";
           "solicitous about the future"
    2: showing hovering attentiveness; "solicitous about her
       health"; "made solicitous inquiries about our family"

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "solicitous":
   accommodating, accommodative, affable, agitated, agreeable,
   all-overish, anxious, anxioused up, apprehensive, ardent, athirst,
   attentive, avid, bothered, careful, caring, cautious, circumspect,
   civil, complaisant, concerned, considerate, courteous, curious,
   deferential, delicate, desirous, disquieted, disturbed, eager,
   earnest, fair, fearful, foreboding, graceful, gracious, heedful,
   helpful, impatient, in a pucker, in a stew, indulgent, keen,
   lenient, loving, mindful, mindful of others, misgiving, nervous,
   obliging, on tenterhooks, overanxious, overapprehensive, perturbed,
   polite, raring, regardful, respectful, strained, suspenseful,
   tactful, tender, tense, thirsty, thoughtful, tolerant, troubled,
   uneasy, urbane, worried, zealous