performing or functioning in the best possible manner with the least waste of time and effort; having and using requisite knowledge, skill, and industry; competent; capable: a reliable, efficient assistant.
Marengo is a village in Morrow County, Ohio, United States. The population was 342 at the 2010 census. Marengo is south of Mount Gilead, the county seat.
The 2016 Marengo, Illinois, population is 7,503. There are 1,500 people per square mile (population density).