Degrade

abbauen

(to reduce in quality or purity)

degradieren

(to lower in value or social position)

erodieren

(to reduce in altitude or magnitude, as hills and mountains; to wear down)

herabsetzen

(to lower in value or social position)

herabstufen

(to lower in value or social position)

herunterstufen

(to lower in value or social position)

vermindern

(to reduce in quality or purity)