1. Of snow or ice, to melt partially, becoming sloppy and wet in the process. The ice along the river began slushing up as the cold snap finally subsided.
2. To cause something to turn into slush. In this usage, a noun or pronoun can be used between "slush" and "up." I like to freeze fruit juice in ice cube trays, then put them in the blender and slush them up with some fresh fruit and yogurt. The warm sun began immediately slushing up the snow in the front yard.
3. To cover or splatter something with slush. In this usage, a noun or pronoun can be used between "slush" and "up." Would you go out and scrape the melted snow off the windscreen for me? I don't want to slush up my new suede boots. The workers slushed my floor up as they trudged in and out of the house in their work boots.
to become messy with slush. As the winter storm increases in intensity, the roads will slush up and become impassable. After an hour of snow and rain, the roads were so slushed up that we could not travel.
in. to drink liquor; to get drunk. They slushed up for a while and went out to look for some chicks.
mod. alcohol intoxicated. I hate to come home slushed and wake up everybody. I have to sing, you see.