Source : Webster's Revised Unabridged Dictionary (1913)

Feebly \Fee"bly\, adv.
   In a feeble manner.

         The restored church . . . contended feebly, and with
         half a heart.                            --Macaulay.

Source : WordNet®

feebly
     adv 1: in a faint and feeble manner; "the lighthouse, flashing
            feebly against the sleet-blurred, rocky backdrop of
            the coast of north west Norway"
     2: in a halting and feeble manner; "reform, in fact, is, rather
        feebly, on the win"