Transmog
Short for transmogrify, a portmanteau of "transfigure" and "modify", the term transmog is commonly used in video games. It refers to a feature where players can change the appearance of a character's item or piece of equipment without affecting its stats or gameplay properties. The image shows a Demon Hunter character from World of Warcraft with a transmogrified Druid gear set.
Transmog usage explained
In most RPGs (role-playing games) and MMORPGs (massively multiplayer online role-playing games), players acquire and cycle through many pieces of gear as they progress through the content. Consequently, players may end up with a piece of equipment with better stats but an appearance they don't like.
In-game transmogrification systems allow players to take the appearance of one item they visually like and apply it to another item with the preferred stats. This way, players can customize their character's look without sacrificing combat or gameplay effectiveness.
World of Warcraft players can use Wowhead's dressing room tool to preview and experiment with different appearance and feature combinations for characters of all types.