actus reus ac·tus·reus uncommon noun 1. activity that transgresses moral or civil law “he denied any wrongdoing” Synonymswrongdoingwrongful conductmisconductactus reus Related words Word family misconduct Broader terms activity Narrower terms brutalizationtrespasstortmalversationmisbehaviorderelictionmalfeasancemisfeasance WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.