hazardous

adjective

1 we work in hazardous conditions:

dangerous, risky, unsafe, perilous, precarious, insecure, tricky, unpredictable, uncertain, high-risk, touch-and-go, fraught with danger;

informal dicey, hairy, sticky, iffy;

British, informal dodgy;

North American, informal gnarly;

archaic or humorous parlous.

▷antonyms safe; secure.

2 a hazardous venture:

chancy, uncertain, undependable, unpredictable, precarious, speculative.

▷antonyms certain.

hazardous Oxford Dictionary of English