dangerous
adj.adj. likely to cause harm, injury, or damage. You use this to describe things that are not safe.
adj. likely to cause injury, pain, harm, or loss. Often used to describe physical environments, activities, or individuals that pose a significant risk.
It is dangerous to walk on the thin ice.
The mountain road becomes extremely dangerous during the winter months when heavy snow covers the sharp turns.
While the chemical is stable under normal laboratory conditions, it becomes highly dangerous if exposed to direct sunlight or high temperatures for extended periods.
From Middle English dangerous (“difficult, severe, domineering, arrogant, fraught with danger”), daungerous, from Anglo-Norman [Term?], from Old French dangereus (“threatening, difficult”), from dangier. Equivalent to danger + -ous. Displaced native Old English frēcne.
Commonly followed by the preposition 'for' or an infinitive 'to' phrase.