(1):
(superl.) Cheerful; genial; as, a sunny disposition.
(2):
(superl.) Of or pertaining to the sun; proceeding from, or resembling the sun; hence, shining; bright; brilliant; radiant.
(3):
(superl.) Exposed to the rays of the sun; brightened or warmed by the direct rays of the sun; as, a sunny room; the sunny side of a hill.
(4):
(n.) See Sunfish (b).