"Big bruise" is a phrase used to describe a large, visible mark on the skin that happens when blood vessels under the skin get damaged. It can be caused by an injury or trauma. Full definition
Luckily, she was never seriously hurt — though she got her first big bruise on the noggin from the door frame attack. (momtricks.com)
Captain America and Iron Man lead warring factions of Earth's Mightiest Heroes into battle against one another, but the two biggest bruises of the Marvel Universe — Thor (Chris Hemsworth) and Hulk (Mark Ruffalo)-- are sitting courtside. (inverse.com)
A few days after that, I suffered a personal loss (as the saying goes, we never thought it would happen to us), then a few days later, I slipped and fell down the concrete stairs at home (earning myself a big bruise on my back and pigeon size bruises on my right arm). (cookingninja.com)