senior summer 

The summer before your senior year in highschool. The last summer you and your classmates have together. Senior Summer is said to be the best summer of your life.

"You ready for senior summer?"
"Only since the first day of freshman year."

senior summer by you'rewrong July 6, 2015

Summer senior 

A high school kid who has finished their junior year and who has immediately fallen off the boat and has increased their chances of not graduating. (Usage of drugs, alcohol, etc. are often the cause)

Did you see John go on that 72 hr bender right after his English exam?
Yeah man he became a summer senior very quickly.

Summer senior by YourMomPeakedInHighSchool May 19, 2021