abacost/ˈæ.bə.kɒst/EtymologyFrom French. A contraction of à bas le costume (“down with the western suit”)nounA short- or long-sleeved button-up jacket, worn without a shirt, that was promoted in Zaire under the regime of Mobutu Sese Seko.“Wearing a collarless jacket called the abacost that reflected the style of chairman Mao, Mobutu outlawed the traditional suits and business dress of the West.”