1: of or resembling Proteus in having a varied nature or ability to assume different forms
2: displaying great diversity or variety: versatile
Proteus was the original master of disguise. According to Greek mythology, the grizzled old shepherd of Poseidon's sea creatures possessed the gift of prophecy but didn't like to share his knowledge. Proteus would escape those who wanted to question him by changing his shape. The only way to get a straight answer from him was to sneak up behind him during his midday nap and hold onto him (while he frantically changed from shape to shape) until he eventually revealed what he knew. The adjective protean describes anyone or anything that is as mutable and adaptable as the mythological sea-shepherd.