The word "treacherous" means untrustworthy or deceitful, someone or something that cannot be relied upon because they may harm or betray you. Full definition
The Book Of Henry is a very bizarre affair, stuck in treacherous waters between kids» movie, terminal illness melodrama and hardboiled film noir. (independent.co.uk)
The global forces driving these changes are converging on a narrow stretch of treacherous water that stands between the oil sands and the world. (thetyee.ca)
DARPA wants to see a robotic workhorse navigate treacherous terrain on its own by the end of the year, in preparation for possible deployment to Afghanistan or Iraq (scientificamerican.com)