• (a.) Diminishing the energy of organs; reducing excitement; as, a debilitant drug.
De·bil'i·tant adjective [ Latin debilitants , present participle] (Medicine) Diminishing the energy of organs; reducing excitement; as, a debilitant drug. 
Type: Term Pronunciation: dĕ-bil′i-tant Definitions: 1. Weakening; causing debility. 2. Obsolete term for a quieting agent or one that subdues excitement.