perdurable (adj.)
- abiding
- aged
- ageless
- ancient
- antique
- ceaseless
- chronic
- constant
- continual
- continuing
- continuous
- dateless
- durable
- endless
- enduring
- eternal
- evergreen
- everlasting
- hardy
- illimitable
- immemorial
- immutable
- incessant
- indestructible
- infinite
- interminable
- inveterate
- lasting
- long-lasting
- long-lived
- long-standing
- long-term
- macrobiotic
- never-ending
- nonstop
- perennial
- permanent
- perpetual
- persistent
- persisting
- remaining
- sempiternal
- stable
- steadfast
- steady
- timeless
- tough
- unceasing
- unending
- unfading
- uninterrupted
- unremitting
- vital
