Open English Wordnet
Adjectives
(s)ageless, aeonian, eonian, eternal, everlasting, perpetual, unending, unceasingcontinuing forever or indefinitely“the ageless themes of love and revenge”,
“eternal truths”,
“life everlasting”,
“hell's perpetual fires”,
“the unending bliss of heaven” (s)endless, eternal, interminabletiresomely long; seemingly without end“endless debates”,
“an endless conversation”,
“the wait seemed eternal”,
“eternal quarreling”,
“an interminable sermon”