The state of being a senior in high school, after receiving an admission to the university or college of your choice. It is the point when one is almost incapable of taking school seriously, because a good average is no longer necessary.
Symptoms of senioritis are lower grades, increased partying, and a lot more sleep and free time.
She already got into McMaster, with a 95 average. Now all she has to maintain is a 70. I think she's about to come down with a serious case of senioritis