Translation guide
The English word "pest" covers a wide range of annoying or harmful living things, from insects and rodents to troublesome people. In Japanese, there is no single perfect equivalent; the best translation depends on what kind of pest you mean.
Refers to insects that damage crops, infest homes, or bite/sting.
The standard word for harmful insects in agriculture, gardening, or household contexts. Literally 'harmful insect'.
This plant has pests on it.
Farmers struggle with pest control.
General word for insect or bug. In context, it can mean pest, especially when the harmful nature is clear.
There's a bug (pest) in the kitchen.
Technically means 'harmful animal' but sometimes used broadly for pests including larger insects or vermin. More common for mammals.
In this area, damage to crops by pests (animals/insects) is serious.
Refers to mice, rats, or other small animals that invade homes or damage property.
Refers to a person who is a nuisance, bothersome, or persistently irritating.
Literally 'troublesome person', a common way to call someone a pest or nuisance.
He's a pest at the workplace.
A person who causes trouble or annoyance. '迷惑' means nuisance or annoyance.
That customer is a real pest.
Very casual and somewhat rude slang for an annoying person. 'うざい' means annoying/irritating, '奴' is a rough word for guy/person.
Use only among close friends; can be offensive.
That guy is such a pest.
Refers to something (not necessarily living) that is a persistent annoyance.
害虫 (gaichū) is for insects and similar small arthropods. 害獣 (gaijū) is for mammals and sometimes larger animals. In everyday conversation, people often just name the specific creature (e.g., ゴキブリ for cockroach, ネズミ for rat) rather than using the umbrella term.
Calling someone 害虫 or 害獣 would be extremely insulting and unnatural. Use 厄介者 or 迷惑な人 instead.
It seems there are pests (rats) in the attic.