Translation guide
Describes someone who is incompetent, contributes nothing, or is a burden. Japanese expressions range from mild to harsh insults, and the best choice depends on context and relationship.
To call someone useless in a general, often insulting way, implying they lack ability or are worthless.
Literally 'useless person'. Common and direct, but can be harsh. Used for someone who fails to be helpful or productive.
彼は本当に役立たずだ。
He's really a useless person.
Means 'incompetent' or 'inept'. Often used as a noun or adjective. Stronger and more formal than 役立たず.
あんな無能はクビだ。
That incompetent person should be fired.
A softer, more descriptive phrase: 'a person who is not useful'. Less insulting than 役立たず.
彼は役に立たない人だと思う。
I think he's a useless person.
A stronger insult combining 'useless' and 'good-for-nothing'. Very harsh and emotional.
あの役立たずのろくでなし！
That useless good-for-nothing!
To describe someone who is a drain on resources or depends on others without contributing.
Literally 'grain-waster'. A harsh term for a person who is a burden on society or family, a freeloader.
彼はただの穀潰しだ。
He's just a freeloader.
Means 'parasite'. Used metaphorically for someone who lives off others. Very insulting.
Literally 'baggage'. A milder, somewhat indirect way to say someone is a burden. Can be used in family or work contexts.
To express extreme contempt, often in casual or vulgar language.
Means 'trash' or 'scum'. Very common slang for a worthless person. Harsh and insulting.
あいつはクズだ。
That guy is trash.
Literally 'garbage'. Similar to クズ, used to devalue a person completely.
お前はゴミだ。
You're garbage.
Means 'dregs' or 'scum'. Even more derogatory than クズ, often used in rough male speech.
てめえはカスだ。
You're scum.
To describe someone who fails to perform a particular function or job.
Adjective meaning 'useless'. Can modify a role noun to specify the context.
彼は役に立たない上司だ。
He's a useless boss.
Means 'unusable' or 'can't use'. Often used for a person who is incompetent in a practical sense.
あの新人は使えない。
That new guy is useless.
Words like 役立たず, クズ, and 穀潰し are extremely insulting and can permanently damage relationships. Use with extreme caution, if at all. In many situations, it's better to describe the behavior rather than label the person.
To criticize without being overly harsh, use phrases like あまり役に立たない (not very useful) or ちょっと頼りない (a bit unreliable).
あの男は社会の寄生虫だ。
That man is a parasite on society.
He's a burden on the team.