<p><strong>Adverb</strong></p><ul><li>in the best possible manner with the least waste of time and effort; capably or competently: Getting this many people to pass information among themselves efficiently, let alone come up with a coherent plan that everybody understands, requires practice.</li><li>in a satisfactory and economical way: The product they are donating will give our volunteers the proper materials to build our homes as efficiently as possible.</li><li>in a way that utilizes a particular resource with the least waste (usually used in combination): The lighter your car is, the more fuel-efficiently it will drive.</li></ul>