Interminable, a.
Etymology: [L. interminabilis: cf. F. interminable. See Terminate.]
Without termination; admitting no limit; boundless; endless; wearisomely protracted; as, interminable space or duration; interminable sufferings. That wild interminable waste of waves. Grainger.
Syn. -- Boundless; endless; limitless; illimitable; immeasurable; infinite; unbounded; unlimited.
Shades of meaning
Fernald has no entry of its own for interminable; he lists it under eternal, infinite.
Where he writes about it:
Everlasting and endless are both used in a limited sense of protracted, indefinite, but not infinite duration; as, the everlasting hills; endless debates; so we speak of interminable quarrels. — from eternal
Synonyms
eternalinfiniteabsoluteboundlesscountlessdeathlessendlesseonianever-livingeverlastingfadelessillimitableimmeasurableimmortalimperishableinnumerablelimitlessmeasurelessnever-endingnever-failingnumberlessperennialperpetualtimelessunboundedunceasingunconditionedundyingunendingunfadingunfailingunfathomableunlimitedunmeasuredwithout end