WordNet (r) 3.0 (2006):

messily
    adv 1: in a messy, untidy manner; "Rossi spat very deliberately,
           and very messily, upon Durieux's party card" [syn:
           messily, untidily]

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "messily":
   airily, any old way, any which way, anyhow, bunglingly, carelessly,
   casually, clumsily, cursorily, disregardfully, forgetfully,
   haphazardly, heedlessly, helter-skelter, hit and miss, hit or miss,
   inattentively, inconsiderately, offhand, offhandedly,
   once over lightly, perfunctorily, promiscuously, recklessly,
   regardlessly, slapdash, sloppily, tactlessly, thoughtlessly,
   unguardedly, unheedfully, unheedingly, unmindfully, unsolicitously,
   unthinkingly, unvigilantly, unwarily