The Collaborative International Dictionary of English v.0.48:

Irresolute \Ir*res"o*lute\, a. [Pref. ir- not + resolute: cf. F.
   irr['e]solu, L. irresolutus not loosened.]
   Not resolute; not decided or determined; wavering; given to
   doubt or irresolution.
   [1913 Webster]

         Weak and irresolute is man.              --Cowper.

   Syn: Wavering; vacillating; undetermined; undecided;
        unsettled; fickle; changeable; inconstant. --
        Ir*res"o*lute*ly, adv. -- Ir*res"o*lute*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

irresolutely
    adv 1: lacking determination or decisiveness [ant: resolutely]