adverb
Describes a calm, unhurried action, often with a sense of quiet purpose. Not as common as ゆっくり, and carries a slightly literary or refined tone.
彼はやおら立ち上がり、窓を閉めた。
He slowly stood up and closed the window.
adverb
Colloquial use where the action is unexpected or abrupt, contrasting with the more common 'slowly' sense. Often used for dramatic effect in speech or casual writing.
やおら彼が大声で叫び出した。
Suddenly he started shouting loudly.