noun
green snot; greenish nasal mucus
Colloquial term for thick, greenish nasal discharge, often associated with a cold or sinus infection. The 青 (あお) here refers to the greenish color, not blue.
See also: 青洟
風邪をひいて青っぱなが出る。
I have a cold and green snot is coming out.
子供が青っぱなを垂らしている。
The child has green snot running down his nose.
Synonym with the same meaning, but 青洟 (あおばな) is the more standard or slightly less colloquial form. 青っぱな is more emphatic and casual with the inserted っ.
General term for runny nose or nasal mucus, not specifically green. 青っぱな specifically refers to thick, greenish mucus.
Compound of 青 (あお, 'blue/green') + っぱな, an emphatic colloquial form of 洟 (はな, 'nasal mucus'). The っ adds a casual, slightly vulgar nuance.