Common in formal writing about social issues, politics, health, or ideas. Frequently used before nouns such as effect, influence, practice, and ideology.
常見錯誤
The storm had a pernicious effect on the roof.
The storm had a damaging effect on the roof.
Pernicious describes gradual or hidden harm, not immediate physical damage from an event.
He is a pernicious person who lies.
He is a dishonest person who lies.
Pernicious is used for effects and influences, not for people or their character directly.