1935, American English, probably from icky-boo (c. 1920) "sickly, nauseated," which probably is a baby talk elaboration of sick (adj.). Originally a swing lover's term for more sentimental jazz music; in general use, "sticky and repulsive," from 1938. Also a noun, "person with conventional taste in jazz," 1937.
ichthyosis
icicle
icing
ickle
Icknield Way
icky
icon
iconic
iconoclasm
iconoclast
iconoclastic