1. (a.) Causing, or tending to cause, ruin; destructive; baneful; pernicious; as, a ruinous project.

2. (a.) Characterized by ruin; ruined; dilapidated; as, an edifice, bridge, or wall in a ruinous state.

3. (a.) Composed of, or consisting in, ruins.

ablative annihilative ausgespielt baleful baneful bankrupt battered beat-up beaten up bedraggled biodegradable black blasted blighted blowzy broken broken-down calamitous careless cataclysmal cataclysmic catastrophic chintzy consuming consumptive corrosive crippling crumbling deadly decomposable decomposing decrepit degradable deleterious demolishing demolitionary depredatory derelict desolated desolating destroyed destroying destructive devastated devastating dilapidated dire disastrous disintegrable disintegrated disintegrating disintegrative disjunctive disruptive done for done in doomful down-and-out drabbletailed draggled draggletailed dusty erosive fallen fatal fateful finished fratricidal frowzy frumpish frumpy fusty gone to pot gone to seed grievous grubby harmful in rags in ruins informal injurious internecine irremediable kaput loose lumpen messy mildewed moldering moldy moss-grown moth-eaten mussy musty nasty negligent nihilist nihilistic noxious overthrown pernicious poisonous poky ragged raggedy ramshackle ravaged ravaging resolvent ruined ruining run-down rusty scraggly seedy self-destructive separative shabby shattering shoddy slack slatternly slipshod sloppy slovenly slummy sluttish solvent sordid spoiled squalid stale subversionary subversive suicidal tacky tattered time-scarred timeworn tottery toxic tragic tumbledown undone unkempt unneat unsightly untidy vandalic vandalish vandalistic wasted wasteful wasting withering worn wrecked wreckful