Adj. A commonly used word to state and describe a sensed irritant of a small value. Often followed by a period. Commonly but not restricted to use as a single word sentence.
Chase sits down at the table to eat a cookie. Chase finishes the cookie and notices the leftover crumbs on the table. "Mean." Chase says.
A boy puts on a fluffy coat because it is cold. The boy stands there staring at the wall and says "Mean." as the coat is too big.
The dog sees a dead snake laying in the grass. "Mean snake." the dog says.