Headcase
noun, slang ·Uncommon ·College level
Definitions
- 1 A mentally unbalanced, unpredictable person, especially one who displays aggressive behavior. countable, derogatory, informal
""A stockbroker doesn't have 80,000 people sitting behind him just waiting for a mistake," says Jim Fassel, whom fans serenaded with "Fire Fassel!" chants during his final weeks as head coach of the New York Giants last season. "It can drive you crazy." From head coach to head case in three easy steps."
- 2 A genetic sequence that inhibits terminal branching of the trachea and regulates dendrite pruning. uncountable
"Another gene downstream of EcR/Usp is headcase. Screening genes that show genetic interactions with EcR mutants, Loncle and Williams identified headcase as a regulator of dendrite pruning (Loncle and Williams 2012)."
Synonyms
All synonymsExample
More examples""A stockbroker doesn't have 80,000 people sitting behind him just waiting for a mistake," says Jim Fassel, whom fans serenaded with "Fire Fassel!" chants during his final weeks as head coach of the New York Giants last season. "It can drive you crazy." From head coach to head case in three easy steps."
Etymology
From head + case.
More for "headcase"
Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.