What is an unreliable narrator?

It's when a narrator character whose telling of the story is not completely accurate

Explanation:

his tongue, i believe, was bloody and hanging out of his mouth.

he looked as if he were hungry.

he has several wolf-like qualities; a gray coat, sharp claws and yellow fangs.

those eyes made me feel, dear reader, like the end was near.

as i reached for a stick, he moved to the other side of the hill.

panting and hungry, he looked at me, a defenseless human and he snarled.

well i said my prayers, however, he simply turned and limped off. 

attitude toward the subject implied in a literary work.

serious at times, angry, impassioned, and optimistic, but most of all urgent