Artless, a.
1. Wanting art, knowledge, or skill; ignorant; unskillful. Artless of stars and of the moving sand. Dryden.
2. Contrived without skill or art; inartistic. [R.] Artless and massy pillars. T. Warton.
3. Free from guile, art, craft, or stratagem; characterized by simplicity and sincerity; sincere; guileless; ingenuous; honest; as, an artless mind; an artless tale. They were plain, artless men, without the least appearance of enthusiasm or credulity about them. Porteus. O, how unlike the complex works of man, Heaven's easy, artless, unencumbered plan! Cowper.
Syn. -- Simple; unaffected; sincere; undesigning; guileless; unsophisticated; open; frank; candid.
Shades of meaning
Fernald has no entry of its own for artless; he lists it under candid, rustic.
Where he writes about it:
On the other hand, artless, guileless, naive, simple, and unsophisticated express the goodness which comes from want of the knowledge or thought of evil. — from candid