1. of a sudden - Adverb
2. of a sudden - Phrase
happening unexpectedly
Source: WordNetStung by the splendour of a sudden thought. Robert Browning
I was sitting in a chair in the patent office at Bern when all of a sudden a thought occurred to me: "If a person falls freely he will not feel his own weight." I was startled. This simple thought made a deep impression on me. It impelled me toward a theory of gravitation. Albert Einstein
There is a thing that happens when you are not as privileged and you start hanging out with a seedier crowd because you can afford to do the same things, And all of a sudden the big night out is sitting in somebody's trailer, smoking something or getting hold of something to put up to your nose. Eddie Vedder
Merriment is always the effect of a sudden impression. The jest which is expected is already destroyed. Samuel Johnson
It's a weird scene. You win a few baseball games and all of a sudden you're surrounded by reporters and TV men with cameras asking you about Vietnam and race relations. Vida Blue
When someone's wealth improves, all of a sudden their house's columns appear to be crooked. Armenian Proverb