Something that’s so-so is neither very good nor very bad. If you go to a concert and report back that it was so-so, it means that you neither loved nor loathed the show. Rather, it was okay. Mediocre is another way to describe things that are middling or average. Though keep in mind, that describing something as average is, generally speaking, not exactly a glowing review! While this adjective appears on paper to be neutral, in most applications, mediocre suggests at best mere adequacy, as in a car that gets mediocre mileage, or at worst inferiority or poor quality: Mediocre construction makes that building dangerous.
The noun chaos is defined as “a state of utter confusion and disorder.” It is applied to a broad range of situations that lack organization. For example, a virtual work meeting wherein everyone talks over each other and there is no agenda laid out might be described as chaos. Or, on a larger and more serious scale, a poorly managed response to a disaster wherein nobody knows how to get the help they need might be described as chaos. The synonym pandemonium suggests unrestrained disorder marked by panic, uproar, and tumult. This noun, from Pandæmonium, the capital of the underworld in Milton’s Paradise Lost, burns a little hotter, so to speak. Pandemonium implies not just disorder, but also noisy, wild, and possibly even violent activity.
Perturb is a synonym of disturb, but, like most synonyms, the two terms are not exactly interchangeable. Disturb is the more common verb of the two, and it is often used to mean “to interrupt,” as in, Please don’t disturb me when I’m working, or, He kept the TV volume low because he didn’t want to disturb his wife’s nap. Perturb implies more agitation and sometimes annoyance or frustration. The careless actions or insensitive words of a person might perturb someone more attuned to their surroundings. Perturb has a distinct meaning in astronomy, where it means "to cause deviation of a celestial body from a regular orbit," as by the presence of one or more other bodies. This celestial disturbance is called perturbation.