What does weapon Bloom mean?

Bloom is a mechanism in Battle Royale which causes the bullets fired from rapid-fire weapons to not fly to the exact same spot, making them instead randomly “jump” left, right, up or down. In practice, this makes rapid-fire weapons less accurate.

What is Bloom graphics setting?

Bloom is a graphic setting that refers to the effect of natural light, swaying/moving trees, plants, flowers, and etc. It makes the world seem more « alive », as players call it. High Quality Bloom is just Bloom tweaked to a level that seems more realistic.