What is a troublesome adjective?

There isn't a single adjective called "troublesome." The word "troublesome" is itself an adjective, meaning:

* Causing difficulty or annoyance: This is the most common meaning. Example: "The dog's constant barking was a troublesome issue for the neighbors."

* Difficult to deal with: This is similar to the first meaning but implies a more persistent or complex difficulty. Example: "The new software was troublesome to learn."

* Prone to causing problems: This meaning suggests an inherent tendency to cause trouble. Example: "The old car was troublesome and often broke down."

So, "troublesome" is already an adjective, and you might be looking for words that describe something that is troublesome. Here are some examples of other adjectives that could be used to describe something troublesome:

* Difficult

* Problematic

* Annoying

* Frustrating

* Unruly

* Disruptive

* Vexing

* Awkward

* Uncooperative

* Unpredictable

The best adjective to use will depend on the specific context and what you want to emphasize about the troublesome thing.