口水仗

dispute / spat / shouting match

mouth / classifier for things with mouths (people, domestic animals, cannons, wells etc) / classifier for bites or mouthfuls

saliva

surname Shui

water / river / liquid / beverage / additional charges or income / (of clothes) classifier for number of washes

weaponry / to hold (a weapon) / to wield / to rely on / to depend on / war / battle