capricious
- Given to sudden and unpredictable changes of mood, mind, or behavior; governed by whim.
- Characterized by or subject to sudden, seemingly random changes (used of weather, fortune, etc.).
In a sentence
- Her capricious decisions made it impossible for the team to plan more than a day ahead.
- The capricious spring weather swung from warm sunshine to sleet within a single afternoon.
Usage note. Capricious and 'mercurial' overlap but 'mercurial' often connotes quick-witted energy alongside changeability, while capricious stresses arbitrary, motiveless shifts.
Where it comes from
English capricious · entered English early 17th c.
From Italian 'capriccioso', related to 'capriccio' (whim, sudden start), probably from 'capo' (head) and 'riccio' (hedgehog), suggesting the image of hair standing on end in fright. The word entered English in the early 17th century via French 'capricieux'. Some sources note uncertainty about the precise derivation of 'capriccio'.