Slimline is a popular term used to describe something that is slender, thin or streamlined. However, there are several synonyms that can be used in place of slimline. Some of these synonyms include sleek, narrow, slender, trim, and svelte. 'Sleek' refers to something that is smooth, polished and elegant. 'Narrow' is similar to slimline but emphasizes on the thinness and reduced width. 'Trim' describes something that is neat and tidy. 'Svelte' refers to a tall, slender and graceful person. Additionally, words like slight, skinny, and slender all denote a physical build that is lean and slender. In general, each of these synonyms can be used interchangeably with slimline to describe something that is slim or slender.