to sniff; to smell
to sniff around
to scent out; to detect
犬が何かの匂いを嗅いで吠え始めた。
The dog started barking after sniffing something.
犬が花の匂いを嗅いでいます。
The dog is smelling the flowers.
花の香りを嗅ぐと気分が落ち着きます。
Smelling the fragrance of flowers calms me down.