underdeveloped (adj.)youdaoicibaDictYouDict[underdeveloped 词源字典]
1892, in photography, from under + past participle of develop (v.). In reference to countries or regions, recorded from 1949.[underdeveloped etymology, underdeveloped origin, 英语词源]
undeveloped (adj.)youdaoicibaDictYouDict
1736, from un- (1) "not" + past participle of develop (v.). In reference to film, it is attested from 1939.