sudden

American  

[suhd-n] / ˈsʌd n /

adjective

1. happening, coming, made, or done quickly, without warning, or unexpectedly.

   a sudden attack.

   Antonyms:

   gradual

2. occurring without transition from the previous form, state, etc.; abrupt.

   a sudden turn.

   Antonyms:

   gradual

3. impetuous; rash.

4. Archaic. quickly made or provided.

5. Obsolete. unpremeditated.

---

adverb

1. Literary. without warning; suddenly.

noun

1. Obsolete. an unexpected occasion or occurrence.

idioms

1. all of a sudden, without warning; unexpectedly; suddenly. Also on a sudden

sudden British  

/ ˈsʌdən /

adjective

1. occurring or performed quickly and without warning

2. marked by haste; abrupt

3. rare rash; precipitate

---

noun

1. archaic an abrupt occurrence or the occasion of such an occurrence (in the phrase on a sudden )

2. without warning; unexpectedly

adverb

1. poetic without warning; suddenly

sudden More Idioms  

1. see all of a sudden.

---

Related Words

Sudden, unexpected, abrupt describe acts, events, or conditions for which there has been no preparation or gradual approach. Sudden refers to the quickness of an occurrence, although the event may have been expected: a sudden change in the weather. Unexpected emphasizes the lack of preparedness for what occurs or appears: an unexpected crisis. Abrupt characterizes something involving a swift adjustment; the effect is often unpleasant, unfavorable, or the cause of dismay: He had an abrupt change in manner. The road came to an abrupt end.

Other Word Forms

• suddenly adverb
• suddenness noun

Etymology

Origin of sudden

First recorded in 1250–1300; Middle English adjective and adverb sodain, soden, sodan(e), from Middle French soudain, from Vulgar Latin subitānus, from Latin subitāneus “going or coming stealthily,” equivalent to subitus “sudden, arising without warning” + -āneus composite adjective suffix, equivalent to -ānus + -eus; see origin at subito, -an, -eous

Explanation

Anything sudden is abrupt, quick, or unexpected. A sudden rain shower during your picnic is disappointing, while a sudden drop-off in the road ahead can be dangerous if you're on your skateboard. The stock market might take a sudden dive, panicking investors, or your favorite TV show could make a sudden change in plot, confusing you for a couple of episodes. Sudden has been used as an adjective since the 15th century, and it was once a noun, too, meaning "that which is sudden." Today the noun form is obsolete, except in the phrase "all of a sudden."

Example Sentences

That narrow conductive path produces a sudden electrical response similar to a neuron firing.

From Science Daily • Apr. 18, 2026

She can’t expect a sudden polling Surge™ the more people get to know her, since everyone in the state already knows her well.

From Slate • Apr. 18, 2026

I predict a sudden wave of nostalgia for touch screens.

From The Wall Street Journal • Apr. 18, 2026

Then all of a sudden, we were brilliant.”

From Los Angeles Times • Apr. 17, 2026

As he headed off, I had a sudden thought.

From "Flying Through Water" by Mamle Wolo

Related Words

• abrupt
• hasty
• immediate
• precipitous
• quick
• rapid
• swift
• unforeseen
• unusual