Other forms: dicier; diciest
Something that's dicey is unpredictable — and it may even be risky or downright dangerous. Bringing up controversial subjects like politics at Thanksgiving dinner with your relatives can be dicey.
If you fix your motorcycle yourself, you may feel like it's a pretty dicey vehicle for riding on the highway, and when you're not at all sure how you did on your biology final, you might say, "Phew, that was dicey." Dicey is an informal word that comes from the idea of the unknown outcome of "a roll of the dice," from aviator's jargon around 1940.