Pussy is actually short for pusillanimous, the insult has nothing to do with female genitals.

pusillanimous - adjective

Lacking courage; cowardly.

Destitute of a manly or courageous strength and firmness of mind; of weak spirit; mean-spirited; spiritless; cowardly; – said of persons, .

Evincing, or characterized by, weakness of mind, and want of courage; feeble.