Definition of hardballer in US English:

hardballer

noun

US
  • 1A baseball player.

  • 2Slang. A person who is ruthless and uncompromising, especially in politics or business.

Origin

1930s; earliest use found in Star Journal (Sandusky, Ohio). Originally from hardball + -er.

Pronunciation

hardballer

/ˈhɑːdbɔːlə/