Oppilation is a word that refers to the act of clogging or blocking a passage, such as the airways or intestines. Some synonyms for this word include obstruction, blockage, congestion, and occlusion. These words all describe the same general idea of something being hindered or prevented from flowing freely. Other related words include impaction, constriction, and narrowing. These words could be used to describe a range of things, from a clogged sink drain to a medical condition such as a blocked artery. Overall, these synonyms provide a variety of ways to describe the act of obstruction or blockage in different contexts.