Synonyms for Extinct:

adj.

all (adjective)
nonextant.
dead (adjective)
fatal, terminated, deceased, study at deaddead, Perished, departed, parted, ended, obsolete, exterminated, without a survivor, defunct, no longer known, dead, vanished, unknown, annihilated, Passed, late, expired, fallen.
dead, obsolete (adjective)
departed, inactive, gone, ended, fallen, deceased, extinguished, defunct, unknown, vanished, no longer known, lost, archaic, late, terminated, out, exterminated, asleep, lifeless.
forgotten (adjective)
unremembered, forgotten, lost, elapsed, obliterated, gone, Erased, irrecoverable.

n.

new, vanished. extinct (noun)
inactive, quenched, nonextant, extinguished, out, dead.
old fashioned (noun)
Old World, archaic, old-time, antiquated, primitive, dated, old fashioned, low-tech.

Other synonyms:

figuratively, agglutinative, lava, idiomatic, cognate, old fashioned, disyllabic, volcano, volcanic. creole, vanished, figurative, vent, erupt. crater, classical, lifeless. asleep. late. Other relevant words:
elapsed, ended, archaic, obsolete, primitive, exterminated, extinguished, inactive, quenched, figuratively, no longer known, creole, asleep, classical, out, antiquated, vanished, volcanic, late, terminated, unknown, dated, lifeless, agglutinative, vent, nonextant, erupt, cognate, old fashioned, volcano, defunct.

Usage examples for extinct

  1. One theory is, that fruits, like animals and vegetables of former ages, may decline and finally become extinct – Soil Culture by J. H. Walden
  2. It is a most stately old house, standing high in a very wild park, one of the only three places where wild cattle are not extinct – Story of My Life, volumes 1-3 by Augustus J. C. Hare
  3. A tradition of an act of somewhat the same character survived in a Slesvig family, now extinct – A Book of Golden Deeds by Charlotte M. Yonge