Translation guide
The English word "costume" covers several distinct concepts in Japanese. The most common meanings are a disguise or outfit worn for fun (like Halloween), a traditional or folk outfit, and a stage or performance costume. The best Japanese word depends on which meaning you intend.
An outfit worn to pretend to be someone or something else, for fun or at an event.
The most direct equivalent for dressing up in a disguise, especially for Halloween or costume parties. Often used in compounds like 仮装パーティー.
I like dressing up in costume for Halloween.
I'm going to a costume party, so I'm thinking about what to wear.
A loanword from English, often used for costumes in entertainment contexts, but can also refer to fancy dress. Slightly less common than 仮装 for Halloween.
I bought a Halloween costume at that store.
Short for "costume play," specifically dressing up as a character from anime, manga, games, etc. Not used for generic Halloween costumes unless they are character-based.
My hobby is doing cosplay at Comiket.
Clothing that represents a particular culture, region, or historical period.
The standard term for traditional folk costume or ethnic dress. Used for any culture's traditional clothing.
In that country, there is still a custom of wearing traditional costumes.
A general word for clothing or outfit, often used in compounds. Can mean costume but is broader. When referring to traditional dress, 民族衣装 is clearer.
Clothing worn by actors, dancers, or performers for a show.
Specifically refers to costumes for the stage, theater, or dance performances.
I'm in charge of designing the stage costumes.
Can be used alone for performance costumes when context is clear, but 舞台衣装 is more precise.
Also used for stage costumes, especially in modern or Western-style performances.
A piece of clothing worn for swimming, often called a "swimming costume" in British English.
The standard word for swimsuit or swimming costume. Not a costume in the disguise sense.
I went to buy a new swimming costume.
While コスチューム is a loanword, it is not used for traditional folk costumes. Use 民族衣装 instead.
Japan's traditional costume is the kimono.
仮装 is general dressing up in disguise (vampire, witch, etc.). コスプレ is specifically dressing as a specific character from fiction. For a Halloween party, 仮装 is safer unless you are going as a known character.
For Halloween, my friend dressed up as a vampire (仮装), and I did anime cosplay (コスプレ).
彼女は民族衣装を着て踊りました。
She danced wearing a folk costume.
We took photos wearing period costumes.
The dancers' costumes were very gorgeous.
ミュージカルのコスチュームはとても凝っています。
The musical's costumes are very elaborate.