dog–eat–dog 
/ˌdɑ:gˌi:tˈdɑ:g/ adjective
/ˌdɑ:gˌi:tˈdɑ:g/ adjective — used to describe a situation in which people compete with each other for success in a cruel and selfish way ▪ It's a dog-eat-dog business we're in. ▪ dog-eat-dog competitions
