Pernicious is an adjective that is used to describe something which causes great harm or damage especially in a way that is not easily seen or noticed. Gradual or subtle.
- He had a ‘pernicious’ mental illness that he avoided up until it affected him severely.
- What we watch and who we listen to can have a ‘pernicious’ effect on us.
- Habits such as eating junk food, being lazy, not being the best we can be will have a ‘pernicious’ effect if not removed from our lifestyles.