From Latin 'comprōmissum' (a mutual promise to accept arbitration), built from 'com-' (together) and 'prōmittere' (to promise) — originally a legal term for honorable dispute resolution that later acquired connotations of vulnerability and exposure.
Weakened, exposed to danger, or having one's integrity or security undermined
Compromised derives from the verb 'compromise,' which entered English in the 15th century from Old French 'compromis,' past participle of 'compromettre' (to make a mutual promise). The French word descended from Latin 'comprōmissum,' a noun meaning 'a mutual promise to abide by an arbiter's decision,' formed from 'com-' (together) and 'prōmittere' (to send forth, to promise). Latin 'prōmittere' combines 'prō-' (forward) and 'mittere' (to send, to let
In Roman law, a 'comprōmissum' was a formal pact in which both parties in a dispute deposited money with a third party and agreed to accept an arbiter's decision — whoever rejected the ruling forfeited their deposit. The modern sense of 'compromised security' would have baffled a Roman jurist, who associated the word strictly with honorable dispute resolution.