This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means smell so the verb version is to smell.

Although 匂う is technically a neutral term, it often means to smell bad. To emphasize the stinkiness, you can also use the kanji 臭 instead of 匂.

Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You learned this reading with the kanji, so you should be able to read it already!