To devalue something means to cause it to be thought less impressive or less deserving of respect. They spread tales about her in an attempt to devalue her work + devalued de·valued She feels devalued because she knows her husband has had affairs
To devalue the currency of a country means to reduce its value in relation to other currencies. India has devalued the Rupee by about eleven per cent + devaluation devaluations de·valua·tion It will lead to devaluation of a number of European currencies