Economics is a study of choices and how you make those choices can be defined. Be it to maximize utility, to increase profit, or to improve a situation. Here are some:
1) Pareto Efficiency: a state where it is not possible to make one better without worsening another.
2) Pareto Improvement: improvement to noe without worsening another (no one is worse off)
3) Pareto worsening: choice that make one better off at the expense of another.
4) Kaldor-Hicks Improvement: A change is a Haldor-Hicks improvement if the gains from that exchange outweigh the costs (potentially pareto improving)
5) Kaldor-Hicks Efficient: occurs when there are no moves away from a certain position for which gains are greater than losses.