Dangerous
Middle English (in the senses ‘arrogant’, ‘fastidious’, and ‘difficult to please’): from Old French dangereus, from dangier (see danger).
wiktionary
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.
etymonline
dangerous (adj.)
c. 1200, daungerous, "difficult to deal with, arrogant, severe" (the opposite of affable), from Anglo-French dangerous, Old French dangeros (12c., Modern French dangereux), from danger "power, power to harm, mastery, authority, control" (see danger).
In Chaucer, it can mean "hard to please; reluctant to give; overbearing." The modern sense of "involving danger, hazardous, unsafe, risky, liable to inflict injury or harm" is from c. 1400. Other words formerly used in this sense included dangersome (1560s), dangerful (1540s). Related: Dangerously.
