'Swarthy' I believe was Tolkien's preferred term. With the possible exception of the Slavic-sounding Variags of Khand, the Easterlings were intended to be Middle-earth's equivalent to the Asiatic nomad hordes which periodically invaded Europe - Huns, Avars, Turks, Mongols, etc. - so 'swarthy' would seem about right for all but the northernmost of their kind. Compare, for example, modern Turkmens (not Southeast Asian dark or Abo black, but not exactly as snow-pale as the Chinese/Japanese/Korean ideal of beauty either) to fanart of Easterlings from the books.
It's the Far Haradrim who Tolkien intended to be the LOTR equivalent to truly black, sub-Saharan Africans. (The Near Haradrim, the sort who were more heavily represented in Sauron's armies and who fielded those Oliphaunts at the Pelennor Fields, weren't generally described as black but also 'swarthy' and approximated to the Arabs - Middle Easterners and North Africans, of course, are as a rule not 'black' either.)
'Swarthy' I believe was Tolkien's preferred term. With the possible exception of the Slavic-sounding Variags of Khand, the Easterlings were intended to be Middle-earth's equivalent to the Asiatic nomad hordes which periodically invaded Europe - Huns, Avars, Turks, Mongols, etc. - so 'swarthy' would seem about right for all but the northernmost of their kind. Compare, for example, modern Turkmens (not Southeast Asian dark or Abo black, but not exactly as snow-pale as the Chinese/Japanese/Korean ideal of beauty either) to fanart of Easterlings from the books.
It's the Far Haradrim who Tolkien intended to be the LOTR equivalent to truly black, sub-Saharan Africans. (The Near Haradrim, the sort who were more heavily represented in Sauron's armies and who fielded those Oliphaunts at the Pelennor Fields, weren't generally described as black but also 'swarthy' and approximated to the Arabs - Middle Easterners and North Africans, of course, are as a rule not 'black' either.)
Tolkien described them as 'Swarthy' people from a 'dry and arid climate' so...dark skinned desert dwellers.