Synonyms: unalterable, changeless
Definition: remaining the same for indefinitely long times
Similar words: unchangeable
Definition: not changeable or subject to change
Usage: a fixed and unchangeable part of the germ plasm-Ashley Montagu; the unchangeable seasons; one of the unchangeable facts of life
Synonyms: invariant, unvarying, changeless, constant
Definition: unvarying in nature
Usage: maintained a constant temperature; principles of unvarying validity
Similar words: invariable
Definition: not liable to or capable of change
Usage: an invariable temperature; an invariable rule; his invariable courtesy