Inertia, Habit, Momentum
noun
If you have the nature of being lazy it will become a habit. The momentum created by your natural laziness will make it so you can't break out of your lazy cycle.
だせい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
僕は、勉強への意欲は無く、ただ惰性で大学へ通っていました。
I had no will to study, I simply attended university out of habit.