がする

The expression がする is used to describe sensory perceptions – things you smell, hear, taste, or feel. The noun before がする is always a noun related to one of the senses, and the verb する here means "to be perceived" or "to give off (a sensation)."

Unlike English, where you would say "I hear a sound" or "I smell something," Japanese uses this construction where the sensation itself is the subject (marked by が), and する expresses that it exists or is perceived.

Smell

Used with nouns like におい匂い (smell/scent), いいにおい匂い (good smell), or specific descriptions of smells.

Sound

Used with nouns like おと音 (sound), こえ声 (voice), or onomatopoeia.

Taste

Used with あじ味 (taste) or specific taste descriptions.

Feeling / Intuition

Used with nouns like かんじ感じ (feeling), き気 (sense/feeling), or よかん予感 (premonition).

Conjugation

Since する is a regular verb, it conjugates normally:

• Past: がした
  おおきな大きなおとがした音がした。

  There was a loud sound.
• Negative: がしない
  なん何のあじ味もしない。

  It doesn't taste like anything.
• Polite: がします
  あまい甘いにおいがします匂いがします。

  It smells sweet.

Important note

The noun used with がする must be a sensory noun. You cannot use this pattern with just any noun. Common sensory nouns include: におい匂い、おと音、こえ声、あじ味、かんじ感じ、き気、かんき寒気 (chills)、はきけ吐き気 (nausea)、めまい (dizziness).