The only free and comprehensive online etymological dictionary of the Spanish language
nocente (Adjective) "harmful;" "guilty"
From Latin nocentem, accusative of nocens 'id.' From nocere "to harm." From Proto-Italic *nok-eje- "to cause death," especially a murderous death. From Proto-Indo-European *noḱ-ei̯e- "to cause death," but originally a euphemism that meant "to cause to disappear." Derived from the root *neḱ- "death," "disappearance."
Galician nocer, Catalan noure, French nuire, Italian nuocere
Sanskrit nāśáya- "to make disappear," Old Persian vināθayatiy "he damages"