Some things happen because people plan them; others happen by chance. English has a whole family of words for chance, from happy surprises to small accidents to full-scale disasters.
Key idea
Chance itself: fortuitous, happenstance, fluke. Good luck: serendipity (lucky finds), windfall (unexpected gain), propitious (favorable signs). Bad luck: hapless (unlucky), mishap (a small accident), calamity (a disaster), debacle (a total failure).
Look for the old word hap, which meant luck or chance: it hides in happen, happy, perhaps, hapless, mishap and happenstance.
The ten words
Common mistake
fortuitous first meant "by chance," good or bad; today it is often used to mean lucky. hapless means unlucky, not helpless.
| word | good or bad luck? | size |
|---|---|---|
| fortuitous, happenstance, fluke | just chance (often lucky) | any |
| serendipity | good: a lucky find | small to large |
| windfall | good: an unexpected gain | often large |
| propitious | good signs ahead | (describes a time or sign) |
| hapless | bad: unlucky | (describes a person) |
| mishap | bad | small |
| calamity, debacle | bad: a disaster; a total failure | large |
The old word hap (luck) explains three of these words: hapless is luck-less, a mishap is bad luck, and happenstance is what just happens.