Meaning

adjective involving or causing danger or risk; liable to hurt or harm

adjective causing fear or anxiety by threatening great harm

originFrom 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.

Etymology from Wiktionary, CC BY-SA 3.0