To associate or deal with a particularly malicious, immoral, or unscrupulous person or people; to commit malicious, immoral, or unscrupulous acts. ("Sup" means to eat or have supper.) Primarily heard in UK. Once considered one of the most straight-laced politicians in England, it's come to light that the former Health Secretary has been supping with the devil for years, giving pharmaceutical companies special privileges in exchange for sizable kickbacks. She has been accused of supping with the devil after the activist was spotted having dinner with the CEO of one of the conglomerations her charity opposes.