noun
runny nose; watery nasal mucus
Casual word for a runny nose or the watery mucus itself, often used when someone has a cold or allergies.
風邪で水っぱなが止まらない。
My runny nose won't stop because of a cold.
ティッシュで水っぱなを拭いた。
I wiped my runny nose with a tissue.
Standard, neutral word for nasal mucus or runny nose. 水っぱな is more casual and somewhat childish.
Compound of 水 (みず, water) and 洟 (はな, nasal mucus), with the はな changing to ぱな due to rendaku and gemination. The exact derivation is uncertain, but it likely originated as a colloquial or childish expression.