The term 'sleek, in automotive lingo' can be summarized as a vehicle that has a smooth, aerodynamic design. The crossword solution for this term is 'aero, ' which is an abbreviation for aerodynamics, the study of how air flows around and through objects. Aerodynamics is an important factor in automotive design, as it affects the vehicle's performance, fuel efficiency, and handling. A sleek car is designed to reduce drag and maximize efficiency, making it more efficient and faster than other vehicles.