1. (adj.) To be heavily covered with fur, a natural fuzzy substance known to grow on animals for warmth and protection. 2. (adj.) Of or having to do with anthropomorphics, especially furridom. 3. (n.) One who partakes in the anthropomorphic or furry fandom. 4. (n.) A character of anthropomorphic stories, legend, or fact.
Used as a noun to refer to anthropomorphic, usually humanoid versions of animals--most commonly cat/human hybrids (aka "catgirls"). Almost always humanoid with full-body fur, but specific features can range from mostly human (though cat/dog like ears on top of the head are very common) to more animal like, featuring muzzle, whiskers, and paws. Short for the Japanese word "hentai" and pronounced (at least by the Japanese) "ecchi". See the definition for both of those terms for details, but note that "H" is frequently combined with other words to point out adult content: "H-anime", for example, would be adult anime.