A horizontal bar along the lower front and lower back part of a motor vehicle to help protect it if there is an accident. (Cambridge Dictionary)
A brimming cup or glass. (Merriam – Webster)
Something unusually large. (Merriam – Webster)
Bumpers are bars at the front and back of a vehicle which protect it if it bumps into something. (Collins Dictionary)
A bumper crop or harvest is one that is larger than usual. (Collins Dictionary)
If you say that something is bumper size, you mean that it is very large. (Collins Dictionary)
A horizontal bar fixed across the front or back of a motor vehicle to reduce damage in a collision. (Oxford Dictionaries)
Bumper. Spray Wise.