ageless, aeonian, eonian, eternal, everlasting, perpetual, unending, unceasing -- (continuing forever or indefinitely; "the ageless themes of love and revenge"; "eternal truths"; "life everlasting"; "hell's perpetual fires"; "the unending bliss of heaven")
ceaseless, constant, incessant, never-ending, perpetual, unceasing, unremitting -- (uninterrupted in time and indefinitely long continuing; "the ceaseless thunder of surf"; "in constant pain"; "night and day we live with the incessant noise of the city"; "the never-ending search for happiness"; "the perpetual struggle to maintain standards in a democracy"; "man's unceasing warfare with drought and isolation"; "unremitting demands of hunger")
(Sound)
