The adjective “desultory” has a colorful Latin origin — a “desultorius” was a circus rider who leapt from horse to horse (from the Latin “salire,” meaning “to leap”). The fanciful word was adopted into English, but with negative connotations. The idea of leaping from horse to horse applies to the definition of “marked by lack of definite plan, regularity, or purpose.” Someone with a desultory work history likely has a reputation of jumping from job to job, without plans or notice. You might also hear the adjective used in a neutral context, with desultory comments being those that aren’t connected to the main topic at hand.