Source : Webster's Revised Unabridged Dictionary (1913)

Artlessly \Art"less*ly\, adv.
   In an artless manner; without art, skill, or guile;
   unaffectedly. --Pope.

Source : WordNet®

artlessly
     adv 1: in a crude and unskilled manner; "an inexpertly constructed
            lean-to" [syn: {crudely}, {inexpertly}]
     2: in an ingenuous manner; "she answered the judge's questions
        artlessly" [syn: {ingenuously}]