1. Not fleshy or fat; thin.
2. Containing little or no fat.
3. 1. Not productive or prosperous; meager: lean years.
   2. Containing little excess or waste; spare: a lean budget.
   3. Thrifty in management; economical: "Company leaders know their industries must be lean to survive" (Christian Science Monitor).
4. Metallurgy Low in mineral contents: lean ore.
   Chemistry Lacking in combustible material: lean fuel.

Synonyms: These adjectives mean lacking excess flesh. Lean emphasizes absence of fat: fattened the lean cattle for market.
Spare sometimes suggests trimness and good muscle tone: "an old man, very tall and spare, with an ascetic aspect" (William H. Mallock).
Skinny and scrawny imply unattractive thinness, as with undernourishment: The child has skinny legs with prominent knees. "He [had] a long, scrawny neck that rose out of a very low collar" (Winston Churchill).
Lank describes one who is thin and tall, and lanky one who is thin, tall, and ungraceful: "He was . . . exceedingly lank, with narrow shoulders" (Washington Irving). The boy had developed into a lanky adolescent.
Rawboned suggests a thin, bony, gangling build: a rawboned cowhand.
Gaunt implies boniness and a haggard appearance; it may suggest illness or hardship: a white-haired pioneer, her face gaunt from overwork.