to speak or behave in a way that shows you are very angry.
After her speech, people who she had criticized were spitting blood.
spit blood
To strongly express one's anger, typically verbally. Unless you want to get yelled at, stay away from the boss today—he's spitting blood over that printing mishap.
spit blood
be very angry. informal
spit ˈblood/ˈvenom/ˈfeathers
show that you are very angry; speak in an angry way: That man made me so angry that by the end of the meeting I was spitting blood!