B1
an infectious illness which is like a very bad cold, but which causes a fever
Dictionary examples:
My flu turned me into a human burrito, wrapped in blankets. (0.0)
The flu made me so hot, I could fry an egg on my forehead! (0.0)
My flu turned my nose into a leaky faucet that wouldn't stop running. (0.0)
I had the flu last week. (14.7)
a flu virus (26.6)