'artly' originates from English, formed from the noun 'art' plus the adjectival/adverbial suffix '-ly', where 'art' ultimately comes from Latin 'ars' meaning 'skill' or 'craft'.

'art' came into English via Old French 'art' from Latin 'ars, artis'; the suffix '-ly' developed from Old English '-lic' (later '-ly'), and the combination produced forms like 'artly' in Middle English, which have been used historically though the word is now rare or archaic.

Initially it meant 'in the manner of art or skill'; over time it has retained this core sense but is now rare and often carries nuances of craftiness or sly cleverness in modern descriptions.