It's one of the most common verbs in English, used in a wide range of contexts, from simple tasks to complex actions. Definition of do 1 verb from the Oxford Advanced Learner's Dictionary. [transitive] do something used to refer to actions that you do not mention by name or do not know about. What are you doing this … 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. To behave or conduct oneself; act: Do as I say and you won't get into trouble. To get along; fare: students who do well at school. To carry on; manage: I could do without your interference. When you do something, you take some action or perform an activity or task. Do is often used instead of a more specific verb, to talk about a common action involving a particular thing. Do is a word of vehement command, or earnest request; as, help me, do; make haste, do. That talk show host just doesn't do subtle.