"Sleek lines" refers to smooth, elegant, and well-defined contours or shapes. It typically describes something that has a modern, streamlined appearance, like a car or a piece of furniture. Full definition
The exterior is defined by sleek lines and stylish touches, such as chrome accents and available LED headlights. (liptontoyota.com)
The 19 - inch - high shaft creates sleek lines when skinny jeans are tucked in, and woven leather details add character to the back. (bestproducts.com)
Great style and sleek lines make the car attractive. (autolist.com)