fortuitous

Word family

• fortuitously
  adverbC1
• fortuitousness
  nounC2

Synonym discussion

Sense: adjective/1

All five words describe events that happen without deliberate planning, but they differ in where they place the emphasis. 'Fortuitous' (C1, formal) anchors the meaning in chance — the outcome may be good, but the defining feature is that it was unplanned. 'Lucky' (A2–B1, everyday) focuses squarely on a favourable outcome, regardless of whether chance was involved. 'Coincidental' (B2) refers specifically to two events happening at the same time or in the same place by accident. 'Serendipitous' (C2, literary) describes a happy accident that leads to something valuable, like finding exactly what you needed while looking for something else. 'Unexpected' (B1) is the broadest — it simply means something surprised you, with no implication about luck. For example: 'It was fortuitous that we met at the airport' (chance encounter, good result); 'It was lucky we met' (the meeting helped us); 'It was purely coincidental that we were on the same flight' (no planning, but not necessarily good); 'Our meeting was serendipitous — she had the one book I needed' (happy accident with value).

Common collocations

Etymology

Comes from Latin 'fortuitus', meaning 'happening by chance', which is related to 'fors' (chance, luck). The word entered English in the mid-1600s. For centuries it meant only 'by chance', with no suggestion of a good or bad result. The association with good luck developed later, in the 1900s, and is now so common that many dictionaries list it as a standard meaning. However, careful writers still prefer 'fortunate' for pure luck and 'fortuitous' for unplanned events that happen to turn out well.