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):

solicitousness
    n 1: a feeling of excessive concern [syn: solicitude,
         solicitousness]