mid-14c., "a plotting of evil, unlawful design; a combination of persons for an evil purpose," from Anglo-French conspiracie, Old French conspiracie "conspiracy, plot," from Latin conspirationem (nominative conspiratio) "agreement, union, unanimity," noun of action from past-participle stem of conspirare "to agree, unite, plot," literally "to breathe together" (see
conspire).
Earlier