GRAPO uncommon noun 1. an armed wing of the (illegal) Communist Party of Spain; seeks to overthrow the Spanish government and replace it with a Marxist-Leninist regime “GRAPO is vehemently opposed to the United States” SynonymsFirst of October Antifascist Resistance Group Related words Broader terms terrorist organization WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.