Antonyms of adj ruinous

2 senses of ruinous

Sense 1
catastrophic, ruinous -- (extremely harmful; bringing physical or financial ruin; "a catastrophic depression"; "catastrophic illness"; "a ruinous course of action")

INDIRECT (VIA harmful) -> harmless -- (not causing or capable of causing harm; "harmless bacteria"; "rendered the bomb harmless")

Sense 2
blasting, ruinous -- (causing injury or blight; especially affecting with sudden violence or plague or ruin; "the blasting effects of the intense cold on the budding fruit"; "the blasting force of the wind blowing sharp needles of sleet in our faces"; "a ruinous war")

INDIRECT (VIA destructive) -> constructive -- (constructing or tending to construct or improve or promote development; "constructive criticism"; "a constructive attitude"; "a constructive philosophy"; "constructive permission")

Similarity of adj ruinous

2 senses of ruinous

Sense 1
catastrophic, ruinous -- (extremely harmful; bringing physical or financial ruin; "a catastrophic depression"; "catastrophic illness"; "a ruinous course of action")
       => harmful (vs. harmless) -- (causing or capable of causing harm; "too much sun is harmful to the skin"; "harmful effects of smoking")

Sense 2
blasting, ruinous -- (causing injury or blight; especially affecting with sudden violence or plague or ruin; "the blasting effects of the intense cold on the budding fruit"; "the blasting force of the wind blowing sharp needles of sleet in our faces"; "a ruinous war")
       => destructive (vs. constructive) -- (causing destruction or much damage; "a policy that is destructive to the economy"; "destructive criticism")