insomnia definition
Full Definition of INSOMNIA. : prolonged and usually abnormal inability to get enough sleep. â inÂ·somÂ·niÂ·ac \-nÄ-Ëak\ adjective or noun. See insomnia defined for English-language learners.See insomnia defined for kids.ull Definition of INSOMNIA. : prolonged and usually abnormal inability to get enough sleep. â inÂ·somÂ·niÂ·ac \-nÄ-Ëak\ adjective or noun. See insomnia defined for English-language learners. See insomnia defined for kids.