ˈrüə̇nəs, ˈru̇ə̇- adjective
Etymology: Middle English ruinose, from Late Latin ruinosus, from Latin ruina ruin + -osus -ose — more at ruin
1. : fallen into decay or dilapidation : ruined
the high paling was broken by the mossy and ruinous posts of an old gateway — John Buchan
2. : causing or tending to cause ruin : destructive , disastrous , pernicious
the excessive wages paid for unskilled labor were ruinous to the farmer — Ellen Glasgow