Unfashionable with

ダサい is negative slang for clothing or style that seems unfashionable or lame. Speakers use it as a blunt criticism, and writers tend to put the ダサ portion in katakana.

Related expressions include:

  • 恰好(かっこ)よくない (not good-looking; not stylish)
  • 恰好(かっこ)(わる)い (bad-looking)
  • おしゃれじゃない (not stylish; not smartly dressed)

Depending on context, English equivalents include “unfashionable”, “uncool”, “lame”, and “dorky”.

Further Reading

Examples

Dorky shirt my mom bought me with ダサイ

Learn the meaning and usage of the vocabulary ダサい in Japanese, with examples from manga.
からかい上手の高木さん » Volume 7 » Page 91

Nishikata and Takagi meet up at the library to study. Although it’s hot out, and Nishikata ran to make it to the library on time, he refuses to remove his sweater.

西片(にしかた):
今日(きょう)(ティー)シャツは… (かあ)さんが()ってきたなんかダサイやつ!!」
“Today's T-shirt is...some dorky thing my mom bought me!!”

Lame monkeys with ダサい

Learn the meaning and usage of the vocabulary ダサい in Japanese, with examples from manga.
くノ一ツバキの胸の内 » Volume 1 » Page 70

Housenka from the monkey squad appears before the dog squad, challenging them to a battle for their squad name. Before she can cause any trouble, Tsuwabuki and Mokuren from her squad appear to stop her. Housenka claims this is their chance to become the dog squad.

ホウセンカ:
(サル)なんてダサいのはもう… ぐっ」
“I'm over this lame monkey thing...gwa!”
ツワブキ:
(サル)ダサくないぞ。」
“Monkeys are not lame.”