It refers to a type of flightless, aquatic bird.
However, it can be used as a verb in very specific contexts:
* Informal: "I'm going to penguin down to the beach" (meaning to waddle or walk in a way that resembles a penguin).
* Technical: "The robot was programmed to penguin its way across the ice" (meaning to move in a specific, penguin-like manner).
These uses are rare and mostly used for humorous effect or in specific technical contexts.