Synonym: abrupt, hasty, impetuous, impulsive, unexpected, unforeseen. Antonym: gradual. Similar words: all of a sudden, buddy, added, a good deal, a good deal of, deny, dense, denial. Meaning: ['sʌdn] 
adj. happening without warning or in a short space of time.
adj. happening without warning or in a short space of time. 271. His sudden smile made her go weak at the knees.
272. The opening scene shows them celebrating their sudden deliverance from war.
273. There had to be an inquest on his sudden death.
274. All of a sudden she didn't look sleepy any more.
275. A sudden gust of wind from the open window puffed the candle out.
276. He had a sudden notion to visit all his relatives.
277. They were going like gangbusters, then all of a sudden everything went wrong.
278. A sudden convulsion shook him, and he fell to the ground.
More similar words: all of a sudden, buddy, added, a good deal, a good deal of, deny, dense, denial, wooden, evident, student, density, incident, identify, resident, evidence, tendency, identity, president, diffident, identical, residence, dependent, confident, presidency, by accident, respondent, residential, schadenfreude, presidential.