Lewis & Short

Tantălus (-los), i (Greek collat. form of dat. Tantaleo, after the form Τανταλεύς), m., = Τάνταλος, a king of Phrygia, son of Jupiter, and father of Pelops and Niobe. He was admitted by Jupiter to the feasts of the gods; but, having disclosed their secrets, he was sent for punishment to the infernal regions, where he stood up to his chin in water under an overhanging fruittree, both of which retreated whenever he attempted to satisfy the hunger and thirst that tormented him. A rock also hung over him ever threatening to fall, Hyg. Fab. 82; Ov. Am. 2, 2, 44; id. M. 4, 457; 6, 172; 10, 41; Poët. ap. Cic. Tusc. 1, 5, 10; Cic. Tusc. 4, 16, 35; id. Fin. 1, 18, 60; Hor. Epod. 17, 66; id. S. 1, 1, 68; Tib. 1, 3, 77 al.
Hence,

  1. A. Tantălĕus, a, um, adj., of or belonging to Tantalus: sors, Prop. 2, 17 (3, 9), 5: manus, id. 2, 1, 66: mensa, Stat. Th. 11, 128.
  2. B. Tantălĭdes, ae, m., a male descendant of Tantalus; of Pelops, Ov. Tr. 2, 385; of the grandsons of Tantalus (Atreus and Thyestes): Tantalidarum internecio, Poët. ap. Cic. N. D. 3, 38, 90; so, Tantalidae fratres, Ov. F. 2, 627; of his great-grandson, Agamemnon, id. M. 12, 626; id. H. 8, 45; id. Am. 2, 8, 13; id. F. 5, 307 al.
  3. C. Tan-tălis, ĭdis, f., a female descendant of Tantalus; of Niobe, Ov. M. 6, 211; Stat. Th. 3, 193; Sen. Herc. Oet. 197; of Hermione, daughter of Menelaus, Ov. H. 8, 122: matres, descended from Tantalus, id. ib. 8, 66.