What does "phrenitis" mean?

Madness, especially as caused by inflammation of the brain; encephalitis, encephalomeningitis, or meningitis.

What is a synonym for "phrenitis"?

Common synonyms include: cephalitis, encephalitis, encephalitis.

Pronounced //fɹəˈnaɪtəs//.

//fɹəˈnaɪtəs// noun

noun ·Rare ·Advanced level

Noun

1
Madness, especially as caused by inflammation of the brain; encephalitis, encephalomeningitis, or meningitis. countable, historical, uncountable
"Phrenitis, which the Greeks derive from the word φρήν, is a disease of the mind, with a continual madness or dotage […]."
2
inflammation of the brain usually caused by a virus; symptoms include headache and neck pain and drowsiness and nausea and fever (‘phrenitis’ is no longer in scientific use) wordnet

"Phrenitis, which the Greeks derive from the word φρήν, is a disease of the mind, with a continual madness or dotage […]."

From Latin phrenītis, from Ancient Greek φρενῖτις (phrenîtis), from φρήν (phrḗn, “mind”).

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.