could be used as in "definetly" or "of course"
Jim: Do you have to put your marshmallow in the fire?
Clark: Dude, it's a no brainer, as a rule of thumb campers should put their marshmallow in the fire.
A question with an obvious response.
Dude 1: Will you take the money?
Dude 2: Yes I will! It's a no brainer.
The act of using your brain to make a decision.
It was a brainer to watch SourceFed.
An easy decision made using the brain. As opposed to a 'no brainer', an incorrect term seeing as how all decisions are made using the brain, as pointed out by SourceFed's brilliant Joe Bereta.
"I could save that man's life with a simple marrow donation, it was a brainer."
When you think about a decision and make the right choice. Like a no-brainer but better.
The decision was a brainer
a girl who sucks dick (gives brains)
that nasty hoe is a brainer too
when you're excited to learn something new, eg. math, science. it's basically a boner in your brain a.ka brainer.
professor farnsworth: all of this knowledge is giving me a raging brainer!!!