The quality of being slushy, like when snow is melting and becomes wet and soft.
Slushiness is often seen as messy and not very nice.
Examples:
I don't like the slushiness of the snow on the ground.
The slushiness of the ice made it hard to walk.
The slushiness of the mud made my shoes dirty.
The slushiness of the snow made it fun to play in.
The slushiness of the fruit made it hard to eat.
The slushiness of the cake made it taste bad.