noun
smokers forced to smoke outside; firefly tribe
A colloquial term for people who have to go outside to smoke, often at night, because smoking indoors is prohibited. The name comes from the image of their lit cigarettes glowing in the dark like fireflies.
最近、マンションの外でホタル族を見かけることが増えた。
Lately, I've been seeing more firefly tribe members outside apartment buildings.
彼もホタル族の一人で、夜になるとベランダでタバコを吸っている。
He's also one of the firefly tribe, smoking on his balcony at night.
喫煙者 is a neutral term for 'smoker', while ホタル族 specifically refers to smokers who must smoke outside, often with a slightly humorous or sympathetic nuance.
Compound of ホタル (firefly) and 族 (tribe, group). The term likens the glowing tips of cigarettes seen outside at night to fireflies.