'arty' originates from English, specifically built from the noun 'art' plus the adjectival suffix '-y', where 'art' meant 'skill, craft' (from older sources) and '-y' meant 'characterized by or inclined to'.

'art' itself comes into English via Old French 'art', from Latin 'ars' (genitive 'artis'). The adjective 'arty' developed in English by attaching the productive suffix '-y' to 'art' to form a word meaning 'characterized by art' and later taking on senses of 'artistic' or 'affectedly artistic'.

Initially it meant 'relating to or characteristic of art', but over time it gained the additional sense of 'affectedly artistic' or 'pretentiously stylish', which is common in modern usage.