a person believes in the greater good for the greater number of people; in ethics, it's the theory that the rightness or wrongness of an action is determined by its usefulness in bringing about the most happiness of all those affected by it.
if your not genetically qualified to be a nazi but still agree with most of the things they stand for.... you're a utilitarian.
An item, building/structure, idea, or other noun used rationally, practically, and safely, and not aimed to be attractive: not ostentatious, but rather simple and suitable; functional, efficient, pragmatic, etc.
The utilitarian house—though only 1500 square feet, in the shape of a box, and comprised of merely, a small kitchen, bathroom, and bedroom, was perfectly suitable for John's needs.
A person that has to come up with an extreme hypothetical to justify an action (that is commonly known as immoral) under utilitarianism. Often used to get away with edgy comments and not focus on the issues that those actions have in our current society.
Person 1: "Well, technically rape is morally neutral. If you could save all of humanity from an alien invasion by raping this one girl that would be a moral good"
Person 2: "Shut the fuck Steve, anything can be justified by incredibly stupid hypotheticals, you are just being a utilitarian edgelord"