Definitions:

1. Refers to the practice of making accusations of subversion, disloyalty, or treason without proper evidence, particularly in the context of political repression and anti-communist hysteria in the United States during the early Cold War. NOUN
   • During the 1950s, McCarthyism ruined many careers as people were accused of Communist sympathies without proof.
2. Unscrupulously accusing people of disloyalty. NOUN
   • The era of McCarthyism instilled fear and paranoia throughout American society, leaving a lasting scar on its civil liberties.

Synonyms:

• blacklisting
• political persecution
• red scare tactics
• witch hunt