noun
greenish nasal mucus; green snot
Colloquial term for thick, greenish nasal discharge, often associated with a cold or sinus infection. Compare 青っぱな, which is more emphatic or childish.
See also: 青っぱな
風邪をひいて、青洟が出る。
I have a cold and green snot is coming out.
ティッシュで青洟をかんだ。
I blew my green snot with a tissue.
Irregular kanji usage; 鼻 normally means 'nose', but here it stands for nasal mucus.
Compound of 青 (ao, 'blue/green') and 洟 (hana, 'nasal mucus'). The reading hana becomes bana due to rendaku.