Synonyms for Lifetime:

adj.

durable (adjective)
incessant, everlasting, long, perpetual, durable, perennial, livelong, enduring, lasting, prolonged, long-life, lengthy, interminable, lifelong, eternal.

n.

existential, history, occurrence, coexistence, life cycle. span, things, life expectancy, existence, universe, live. age (noun)
epoch, eon, age, longevity, oldness, time, lastingness, generation, duration, era.
life (noun)
history.
lifelong (noun)
continuing, permanent.
lifetime (noun)
life, lifespan.
point of time (noun)
microsecond, decade, second, day, week, millennium, month, term, semester, century, year, hour, millisecond, minute.
span of animate being's existence (noun)
life, time, existence.

Other synonyms:

existential, occurrence, coexistence. life expectancy, universe, life cycle. span. existence. history. Other relevant words:
history, existential, coexistence, permanent, span, universe, lifespan, life expectancy, existence, life.

Usage examples for lifetime

  1. You had better read a book about this situation, for it is the most surprising affair in a lifetime – Letters from China and Japan by John Dewey Alice Chipman Dewey
  2. He is said to have written in all two hundred and fifty books in the course of his lifetime – A Brief History of the English Language and Literature, Vol. 2 (of 2) by John Miller Dow Meiklejohn
  3. The printed copies, of course, begin with those published in his own lifetime – Milton by John Bailey