sudden
adj.adj. happening very quickly and when you do not expect it. You use this to describe a change or an event that surprises you because it is so fast.
adj. happening, coming, or done quickly and unexpectedly. Often used to describe transitions or events that lack a gradual onset.
The weather changed after a sudden storm.
The driver had to make a sudden stop when a cat ran into the middle of the road.
The sudden departure of the CEO left the board of directors scrambling to find a suitable replacement before the quarterly earnings call.
From Middle English sodeyn, sodain, from Anglo-Norman sodein, from Old French sodain, subdain (“immediate, sudden”), from Vulgar Latin *subitānus (“sudden”), from Latin subitāneus (“sudden”), from subitus (“sudden", literally, "that which has come stealthily”), originally the past participle of subīre (“to come or go stealthily”), from sub (“under”) + īre (“go”). Doublet of subitaneous. Displaced native Old English fǣrlīċ.
Typically placed before the noun it modifies; frequently used in the prepositional phrase 'all of a sudden' to function as an adverb.
It happened very suddenIt happened very suddenlyLearners often use the adjective form 'sudden' when the adverb 'suddenly' is required to modify a verb.