Serious malady is a phrase that can be used to describe a variety of medical conditions. There are many synonyms that can be used to describe this type of illness, including severe illness, life-threatening disease, critical condition, grave illness, and debilitating ailment. These terms all suggest a serious, potentially life-altering health problem. Other synonyms that could be used include terminal illness, chronic disease, and life-threatening condition. When discussing health issues, it is important to choose words that accurately convey the severity of the situation in order to ensure that proper care and attention are given to the patient.