ムカつく

むかつく
verb (godan)
to feel irritated; to be pissed off
1. to feel irritated; to be annoyed; to be pissed off
Slang expression for feeling strong annoyance or anger toward someone or something.
あいつの態度(たいど)にムカつく。
His attitude pisses me off.
ムカつくことを()われた。
Someone said something that annoyed me.
2. to feel nauseous; to feel sick
The original meaning: to feel queasiness or nausea, especially in the stomach.
()がムカつく。
My stomach feels queasy.

SLANG/COLLOQUIAL:
Originally meant "to feel nauseous" (sense 2), but now primarily used as youth slang for "to be irritated/annoyed" (sense 1).

WRITING:
Often written in katakana (ムカつく) to emphasize its slang nature, though hiragana (むかつく) is also used.

RELATED:

  • ムカムカする: to feel nausea; to be irritated (onomatopoeia)
  • イラつく: to be irritated (similar slang)
  • (はら)()つ: to be angry (standard expression)

REGISTER: Casual/informal. Avoid in formal situations.