Antonyms of adj mannered

1 sense of mannered

Sense 1
mannered -- (having unnatural mannerisms; "brief, mannered and unlifelike idiom")

INDIRECT (VIA affected) -> unaffected -- (free of artificiality; sincere and genuine; "an unaffected grace")

Similarity of adj mannered

1 sense of mannered

Sense 1
mannered -- (having unnatural mannerisms; "brief, mannered and unlifelike idiom")
       => affected (vs. unaffected), unnatural -- (speaking or behaving in an artificial way to make an impression)