Have you ever had one of those days?

desultory (des·ul·to·ry): / DES uhl tohr ee /
adjective

(1) marked by lack of purpose or regularity; without constancy, order, or consistency; passing aimlessly from one thing to the next; fitful
(2) disconnected from the main subject; random

[From Latin desultorius meaning “leaping” (literally regarding desultor, a circus rider who leaps from horse to horse), from desilire meaning “to leap down,” from salire meaning “to leap.”]

Usage: Our professor was rather upset with your desultory remarks throughout the class discussion.