unalterable (adj.)
- adamant
- adamantine
- cast-iron
- changeless
- constant
- dour
- firm
- fixed
- flinty
- grim
- hard
- hard-core
- immovable
- immutable
- implacable
- inalterable
- incommutable
- inconvertible
- indefeasible
- inelastic
- inert
- inexorable
- inextensible
- inflexible
- intractable
- intransigent
- invariable
- iron
- irreconcilable
- irretrievable
- irreversible
- irrevocable
- lasting
- noble
- nonreturnable
- nonreversible
- permanent
- relentless
- rigid
- rigorous
- rock-ribbed
- steely
- stern
- stiff
- stubborn
- unaffected
- unaltered
- unbending
- unchangeable
- unchanged
- unchanging
- uncompromising
- undeviating
- unmalleable
- unmodifiable
- unmovable
- unmoved
- unrelenting
- unremitting
- unsusceptible
- unvarying
- unyielding
Nor mourn the unalterable Days
That Genius goes and Folly stays.
