Fetching details from the dictionary...

to harm; to hurt; to injure; to damage; to spoil; to mar; to ruin
to fail to do; to do amiss; to miss one's opportunity to do
to almost do; to come close to doing
無理をすると体の健康を損なうおそれがある。
Overexerting yourself may harm your health.
軽率な発言が会社の信用を損なう結果となった。
Careless remarks ended up damaging the company's credibility.
景観を損なわないよう建物の高さが制限されている。
Building heights are restricted so as not to spoil the scenery.