Being a senior in high school, the word “senioritis” greatly annoys me. Look up the suffix -itis, and you’ll find see “Indicates inflammation of or inflammatory disease” Such as appendicitis, bronchitis, laryngitis, etc. Inflammation of the Seniors? What the hell is that? Am I expected to show up at school with boils all over my skin or something?
Anyways, senioritis obviously has a negative connotation. However, the “afflicition” of senioritis is usually the senior class having more freedom and not wanting to adhere to the rules of the school. The natural desire for freedom is not a bad thing, so senioritis might be better called maturity.
As for the origin of the term, I don’t know really.