Thin one is a term used to describe a person who is physically slim or skinny. There are several synonyms that can be used to describe a thin person, including slender, gaunt, bony, svelte, wiry, lean, lanky, scrawny, and emaciated. Slender refers to a person who is delicately thin and graceful in appearance. Gaunt and bony describe someone who is thin to the point of being unhealthily thin and malnourished. Svelte is used to describe a person who is thin and elegant looking with a sense of style. Wiry and lean describe a person who is slender but still athletic looking. Lanky, on the other hand, describes someone who is tall and thin with long limbs. Scrawny and emaciated describe someone who is extremely thin and sickly looking.