臭
chòu · HSK 5
foul
🦨 自 (self/nose) + 犬 (dog) = a dog using its nose to sniff out smells
Old form shows a nose (自 originally meant nose) over 犬 (dog), since dogs track scent. Meaning drifted from 'smell' to specifically 'bad smell', then figuratively to 'disgraceful'. Modern 嗅 took over the neutral 'sniff' sense.
臭 — 自 (nose) + 犬 (dog)
Originally a pictograph combining 自 (nose) and 犬 (dog), depicting a dog using its nose to sniff out scents. The early meaning was 'to smell,' later extended to 'odor' and then narrowed to 'foul smell.' The 'smell/sniff' sense was preserved in the later character 嗅.