Choose the perfect synonym or antonym for the word

Sudden

/ˈsʌdn/

Happening quickly and unexpectedly without prior warning.

Synonyms:

Her sudden kindness and sympathy was too much for me.

All of a sudden it went squeak!

In sudden fear, he beat loudly upon it.

Late Middle English: from Anglo-Norman French, having Latin roots from subitaneus, based on subitus meaning coming from beneath, unawares.

22 mentions per 1 million words

Often

Hint: Frequency according to COCA