Something that's anarchic is out of control or extremely disorganized. An anarchic classroom has no rules — it most likely has no teacher, either.
Wars and political conflicts are frequently described as anarchic, particularly if they appear to be lawless and chaotic. Any situation that's lacking structure or rules can be called anarchic, like a wild, sugar-fueled birthday party or an anarchic swarm of gulls attacking a plate of French fries on a picnic table. The Greek root word is anarkhos, "without head or chief."