leaner (Adjective) — Lacking excess flesh. ex. "Yon Cassius has a lean and hungry look"
leaner (Adjective) — Lacking in mineral content or combustible material. ex. "lean ore" ex. "lean fuel"
leaner (Adjective) — Containing little excess. ex. "a lean budget"
leaner (Adjective) — Not profitable or prosperous. ex. "a lean year"
leaner (Noun) — (horseshoes) the throw of a horseshoe so as to lean against (but not encircle) the stake.