not happening at regular times; not following any plan or regular pattern; that you cannot rely on synonym unpredictable The electricity supply here is quite erratic. She had learned to live with his sudden changes of mood and erratic behavior. Mary is a gifted but erratic player (= she does not always play well). Irrigation measures will be necessary in areas of erratic rainfall.
NAmE//ɪˈræt̮ɪkli//
adverb He was obviously upset and was driving erratically. His heart beat erratically.See erratic in the Oxford Advanced Learner's DictionaryCheck pronunciation: erratic