In medicine, –itis is a suffix used to indicate disease or inflammation (e.g., tonsillitis). It was extended to refer to made-up ailments or conditions, such senioritis. As an independent word extracted from uses of the suffix, itis is a slang term for the lazy, sleepy feeling one ge...
a suffix occurring in words that denote an inflammation or disease affecting a given part of the body (appendicitis; bronchitis; phlebitis); also forming nouns, often nonce words, that denote an obsessive state of mind or tendency facetiously compared to a disease (electionitis; telephonitis). ...