adjective
1.
Synonyms: natural 5, artless, ingenuous, naive, simple, unaffected, unartificial, unschooled, unsophisticated, untutored
Antonyms: studied
2.
Synonyms: extemporaneous , autoschediastic, extemporary, extempore, impromptu, improvised, offhand, spur-of-the-moment, unrehearsed