xenobioticEnglishOxford New American Dictionaryxenobiotic /ˌzenəbīˈädik, ˌzɛnəbaɪˈɑdɪk / ▸ adjective relating to or denoting a substance, typically a synthetic chemical, that is foreign to the body or to an ecological system: xenobiotic synthesis. ▸ noun (usually xenobiotics) substances that are foreign to the body or to an ecological system.