Sleek (adjective)

1. Smooth, glossy and shiny in appearance.
2. Having a streamlined or well-proportioned form.
3. Having a well-groomed, stylish and sophisticated appearance.
4. Having a smooth and efficient operation or performance.

Origin:

From the middle english word "slek" meaning "smooth and glossy".

Examples:

1. The sleek black car was a real head-turner.
2. The sleek design of the phone makes it easy to hold and use.
3. The sleek hair of the models on the runway.
4. The sleek lines of the new building were impressive.
5. The sleek new airplane was faster and more fuel-efficient than its predecessor.