avoid (someone or something) like the plague
To consciously stay away from someone or something. I didn't do my homework my last night, so I'm avoiding my teacher like the plague. My dog is terrified of cats and avoids them like the plague.
avoid someone/something like the plague
If you avoid someone or something like the plague, you do everything possible to avoid them. I would avoid him like the plague when his wife was around. The athlete must avoid all extra sugar like the plague. Note: The plague is bubonic plague, a disease which killed over 50 million people in Europe and Asia during the 14th century and was referred to as the Black Death.