Meaning

adjective not straightforward or candid; giving a false appearance of frankness; - David Cannadine

adjective marked by skill in achieving a desired end especially with cunning or craft

originFrom art (“skill that is attained by study, practice, or observation”) + -ful (suffix forming adjectives from nouns, with the sense of being full of, tending to, or thoroughly possessing the quality expressed by the noun).

Etymology from Wiktionary, CC BY-SA 3.0