once-in-a-lifetime
Never happening again
Once-in-a-lifetime describes something so rare or extraordinary that it's unlikely to happen again: a once-in-a-lifetime opportunity, a once-in-a-lifetime trip.
The phrase emphasizes uniqueness and urgency—if you miss this, there won't be another.
Often used for major experiences: solar eclipses, dream vacations, career breaks.
Sometimes hyperbolic: This once-in-a-lifetime sale ends Sunday!
Only one exists
- singularOne in number
- unrepeatableImpossible to do again
- unprecedentedNever having occurred before
- exceptionalNotably above the norm
irreplaceable · unparalleled · extraordinary · incomparable · one-of-a-kind · rare · matchless · unmatched
Likelihood of occurrence
- occasionNotable event or moment
- prospectPotential client or opportunity
- openingGap or start
- breakInterrupt continuity
window · crossroads · watershed · milestone · breakthrough · seize · grasp · capitalize
Risky exciting undertaking
- journeyTravel from place to place
- pilgrimageReligious journey to shrine
- hajjMuslim pilgrimage to Mecca
- safariWildlife observation journey
expedition · aurora · eclipse · Everest · Serengeti · Antarctic · Olympics · Carnival
Marriage rite and feast
- birthComing into the world
- graduationCompleting academic requirements formally
- retirementLeaving the workforce permanently
- anniversaryRecurring memorial date
reunion · homecoming · coronation · inauguration · ordination · quinceañera · coming-of-age · proposal
unique
Only one exists
- singularOne in number
- unrepeatableImpossible to do again
- unprecedentedNever having occurred before
exceptional · irreplaceable · unparalleled · extraordinary · incomparable · one-of-a-kind · rare · matchless · unmatched · peerless
chance
Likelihood of occurrence
break · window · crossroads · watershed · milestone · breakthrough · seize · grasp · capitalize · timing
adventure
Risky exciting undertaking
- journeyTravel from place to place
- pilgrimageReligious journey to shrine
- hajjMuslim pilgrimage to Mecca
safari · expedition · aurora · eclipse · Everest · Serengeti · Antarctic · Olympics · Carnival · wonder
wedding
Marriage rite and feast
- birthComing into the world
- graduationCompleting academic requirements formally
- retirementLeaving the workforce permanently
anniversary · reunion · homecoming · coronation · inauguration · ordination · quinceañera · coming-of-age · proposal · ceremony
- one-time thingsonce, single-use, one-off, disposable, nonrecurring
- amazingastonishing, astounding, breathtaking, extraordinary, incredible
once-in-a-lifetimeordinary
Standard, unremarkable
mundane · commonplace · unremarkable · run-of-the-mill · garden-variety
once-in-a-lifetimeforgettable
Unlikely to be recalled
unremarkable · insignificant · humdrum · unexceptional · trivial
lifeless, lifetime, lifelong, lifeboat, lifespan, one-time, lifecycle, lifeforms