vexatious Syllabification: (vex·a·tious)Pronunciation: /vekˈsāSHəs/Translate vexatious | into Italian Definition of vexatious adjective causing or tending to cause annoyance, frustration, or worry:the vexatious questions posed by software copyrights Law denoting an action or the bringer of an action that is brought without sufficient grounds for winning, purely to cause annoyance to the defendant. Derivatives vexatiously adverb vexatiousness noun vexatious in other Oxford dictionaries Definition of vexatious in the British & World English dictionary