Pathetic fallacy is attributing human feelings to inhuman things. If you describe a storm cloud as “angry” or a strong wind as “vengeful,” that’s pathetic fallacy.
A fallacy is a type of mistake, especially an illogical one. The word pathetic can refer to things that involve emotion. The pathetic fallacy is the illogical act of saying that something inhuman has emotions. Although the pathetic fallacy is a kind of flawed logic, that doesn’t mean you should avoid it. Poets use pathetic fallacy all the time in phrases like “the wise moon” or “the generous sun.”