happening quickly and unexpectedly, without any warning
A sudden storm forced the hikers to run for cover.
The company faced a sudden drop in sales after the product recall.
✦ Late Middle English, from the phrase ‘of a soden’, based on Old French sodain, from Latin subitaneus ‘sudden’.
an unexpected event, change, or moment (now rare and mainly literary)
On a sudden, the candles went out, and the hall fell into darkness.
The messenger arrived in a sudden and brought alarming news from the front.
✦ Same origin as the adjective; the noun use arose from Middle English phraseology such as ‘of a soden’ meaning ‘unexpectedly’.
in a quick and unexpected way
The lights went out suddenly during the storm.
A dog suddenly barked, making everyone jump.
✦ from Middle English sodeinli, from sodein (sudden) + -ly
