discursive
Meaning: rambling, lacking order
Usage: The professor’s discursive lectures seemed to be about every subject except the one initially described.
extraneous
Meaning: irrelevant, extra, not necessary
Usage: Personal political ambitions should always remain extraneous to legislative policy, but, unfortunately, they rarely are.
gratuitous
Meaning: uncalled for, unwarranted
Usage: The speaker’s gratuitous insult distracted from an otherwise thoughtful debate.
tangential
Meaning: incidental, peripheral, divergent
Usage: I tried to discuss my salary, but the boss kept veering off into tangential topics.
oblique
Meaning: diverging from a straight line or course, not straightforward
Usage: Martin’s oblique language confused those who listened to him.