noun 1. the qualities of skill, knowledge, and expertise. 2. the full grasp of a subject or skill.His coach didn’t allow him to stop practicing until he had reached mastery.Her mastery of…

noun a person, thing, or action that serves to protect or defend; means of maintaining safety.The government has recently implemented safeguards against the spreading of the disease.Changing one’s password frequently is a…

transitive verb to search through thoroughly, esp. for items to steal; plunder.The thieves ransacked the tomb in search of treasure. See the full entry

noun 1. disregard of, omission of, or failure to do something necessary; carelessness or neglect, esp. when it is habitual.Because of the owner’s negligence, the dog suffered from untreated infections. 2. in…