The Collaborative International Dictionary of English v.0.48:

Competently \Com"pe*tent*ly\, adv.
   In a competent manner; adequately; suitably.
   [1913 Webster]

WordNet (r) 3.0 (2006):

competently
    adv 1: with competence; in a competent capable manner; "they
           worked competently" [syn: competently, aptly, ably,
           capably] [ant: displaying incompetence,
           incompetently]

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "competently":
   ably, adeptly, adequately, adroitly, agilely, amply, aptly,
   artfully, artistically, brilliantly, capably, cleverly, cunningly,
   deftly, dexterously, dextrously, effectively, effectually,
   efficiently, enough, excellently, expertly, featly, handily,
   ingeniously, masterfully, minimally, neatly, nimbly, proficiently,
   resourcefully, satisfactorily, skillfully, spryly, substantially,
   sufficiently, superbly, well, with consummate skill, with finesse,
   with genius, with skill