an infectious disease like a very bad cold, that causes fever, pains and weakness The whole family has the flu. (British English) She's got flu. She was off work for four days because of a bout with the flu. She’s had a nasty dose of flu. CollocationsIllnessesBecoming ill catch a cold/an infectious disease/the flu/(British English) flu/pneumonia/a virus/(informal) a bug get (British English) ill/(North American English) sick/a disease/AIDS/breast cancer/a cold/the flu/(British English) flu/a migraine come down with a cold/the flu/(British English) flu contract a deadly disease/a serious illness/HIV/AIDS be infected with a virus/a parasite/HIV develop cancer/diabetes/a rash/an ulcer/symptoms of hepatitis have a heart attack/a stroke provoke/trigger/produce an allergic reaction block/burst/rupture a blood vessel damage/sever a nerve/an artery/a tendonBeing ill feel (British English) ill/sick/nauseous/queasy be running (British English) a temperature/(North American English) a fever have a head cold/diabetes/heart disease/lung cancer/a headache/(British English) a high temperature/(North American English) a fever suffer from asthma/malnutrition/frequent headaches/bouts of depression/a mental disorder be laid up with/ (British English) be in bed with a cold/the flu/(British English) flu/a migraine nurse a cold/a headache/a hangover battle/fight cancer/depression/addiction/alcoholismTreatments examine a patient diagnose a condition/disease/disorder be diagnosed with cancer/diabetes/schizophrenia prescribe/be given/be on/take drugs/medicine/medication/pills/painkillers/antibiotics treat somebody for cancer/depression/shock have/undergo an examination/an operation/surgery/a kidney transplant/therapy/chemotherapy/treatment for cancer have/be given an injection/(British English) a flu jab/(North American English) a flu shot/a blood transfusion/a scan/an X-ray cure a disease/an ailment/cancer/a headache/a patient prevent the spread of disease/further outbreaks/damage to the lungs be vaccinated against the flu/(British English) flu/the measles/(British English) measles/polio/smallpox enhance/boost/confer/build immunity to a disease See related entries: Ailments and diseases, Being ill Word Origin mid 19th cent.: abbreviation.