expression, suru verb (irregular)
General expression for perceiving a smell. The subject is the smell source, often marked with が. The kanji 匂い suggests a pleasant or neutral smell, while 臭い suggests an unpleasant one.
この花はいい匂いがする。
This flower smells nice.
台所からカレーの匂いがする。
There's a smell of curry coming from the kitchen.
靴下が臭いがする。
The socks smell bad.