What does Clīdē̆s mean in Latin?

Clīdē̆s, a proper noun, means “A group of islands off the coast of Cyprus”.

What is the genitive of Clīdē̆s?

The genitive singular is Clīdum. Clīdē̆s is feminine, third declension.

proper noun · femininethird declension

Clīdē̆s f pl (genitive Clīdum)

A group of islands off the coast of Cyprus
in eodem situ Eleusa insula est, et quattuor ante promunturium ex adverso Syriae Clides, rursusque ab altero capite Stiria, contra Neam Paphum Hiera et Cepia, contra Salamina Salaminiae.1942 translation by H. Rackham In the same neighbourhood is the island of Eleusa, and the four Clides off the cape facing Syria, and again off a second headland Stiria, and towards New Paphos Hiera and Cepia, and towards Salamis the Salaminiae.77 CE – 79 CE, Plinius Maior, Naturalis Historia 5.130

From Ancient Greek Κλεῖδες (Kleîdes).