Synonyms for Perpetual (same or very similar meaning)
WordNet sense 1 (continuing forever or indefinitely):
ageless, eternal, everlasting, unceasing, unending, aeonian, eonian
WordNet sense 2 (continuing or enduring without marked change in status or condition or place):
permanent
WordNet sense 3 (uninterrupted in time and indefinitely long continuing):
ceaseless, constant, incessant, unremitting, never-ending
WordNet sense 4 (continuing in time or space without interruption):
continuous
WordNet sense 5 (occurring so frequently as to seem ceaseless or uninterrupted):
endless
WordNet sense 6 (seemingly without interruption; chiefly restricted to what recurs regularly or frequently in a prolonged and closely spaced series):
continual
From the ODE community, based on WordNet
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