A slicker is a long, loose coat that is worn to keep dry in the rain.
Wearing a slicker can make people think of rainy days and being prepared for bad weather.
Examples:
She wore a yellow slicker in the rain.
I need to buy a new slicker for the wet weather.
The slicker kept him dry during the storm.
His slicker was so big, it looked like a tent!
I have a slicker that can keep me dry even in a hurricane.
The slicker flapped in the wind as she walked.