Translation guide
The English verb 'sniff' covers several distinct actions: inhaling audibly through the nose (often to smell something or when crying), expressing disdain, and detecting something suspicious. Japanese uses different verbs and onomatopoeia for each nuance.
The physical action of drawing air into the nose with a sound, typically to perceive a scent.
The most common verb for sniffing to smell something. Used for both intentional and casual sniffing.
The dog is sniffing the ground.
I sniffed the scent of the flower.
Explicitly says 'sniff the smell', often used when the object of sniffing is a smell rather than a physical object.
I think I sniffed a strange smell.
Onomatopoeic verb mimicking the sound of sniffing, often used for animals or cute, repeated sniffing. Casual.
The cat is sniffing the box.
The involuntary, repeated sniffing sound made when the nose is runny, often from crying or illness.
To make a sniffing sound as a gesture of scorn or disapproval.
To sense or suspect something intuitively, as if by smell. Often used figuratively.
To inhale a substance, often illicit, through the nose.
嗅ぐ (kagu) can take a direct object (the thing being smelled), while 匂いを嗅ぐ (nioi o kagu) explicitly makes 'smell' the object. Both are natural, but 嗅ぐ is more direct and common for physical objects.
sniff the smell of socks
English 'sniff at' (to disdain) cannot be directly translated as ～に嗅ぐ. Use 鼻で笑う or ふんと鼻を鳴らす instead.
I'm sniffling because of hay fever.
She sniffed contemptuously and left the room.
I sniffed something fishy in his story.
Young people sniffing paint thinner is a problem.