Ru″in‐ous (?), a. [L. ruinosus: cf. F. ruineux. See Ruin.] 1. Causing, or tending to cause, ruin; destructive; baneful; pernicious; as, a ruinous project.
After a night of storm so ruinous. Milton.
2. Characterized by ruin; ruined; dilapidated; as, an edifice, bridge, or wall in a ruinous state.
3. Composed of, or consisting in, ruins.
Behold, Damascus... shall be a ruinous heap. Isa. xvii. 1.
Syn. — Dilapidated; decayed; demolished; pernicious; destructive; baneful; wasteful; mischievous.
— Ru″in‐ous‐ly (#), adv. — Ru″in‐ous‐ness, n.