Find out the differences between an MD and DO, and discover the pros, cons, risks, and benefits, and how it may affect health. DO definition: to perform (an act, duty, role, etc.). See examples of do used in a sentence. Do is one of three auxiliary verbs in English: be, do, have. We use do to make negatives (do + not), to make question forms, and to make the verb more emphatic. … Today, you'll learn how to use DO, DOES, DID, and DONE in English. Improve your English fluency by learning everything you need to know about the verb TO DO. Feasible comes from faire, the French verb meaning “to do.” Doable and feasible therefore originally meant literally the same thing: “capable of being done.” 1. To behave or conduct oneself; act: Do as I say and you won't get into trouble. 2. a. To get along; fare: students who do well at school. b. To carry on; manage: I could do without your interference. To do is to act, perform, or undertake. When you do chores, you engage in the activity of cleaning the kitchen or taking out the trash. Do is one of the most frequently used verbs in English. You do many things in a typical day: you might do the dishes, do your job, and later on, do your taxes.