To drive over the speed limit, but still more slowly than everyone else on the road.
Underspeed. Conjugate like any other verb. Jeff undersped the whole time we were in Israel, going 80 kph when the posted limit was 60 kph. Krishnan and I mocked him severely when even a bus passed us at about 100 kph.
In typically four-year academic programs, a fifth-year senior.
Me: "Hey, how are you in my class again? I thought you were a senior last year."
You: "Yeah, I'm a valtimore."