The term 'course of event' refers to the sequence of occurrences that take place over a period of time. Antonyms for this phrase can express the opposite of a sequence, such as a random or chaotic series of events. Words that can be used as antonyms for 'course of event' include haphazard, arbitrary, unorganized, unplanned, aimless, and erratic. These words suggest that events are not following a specific path or timeline, but are rather occurring without any particular order or reason. Alternatively, the antonyms could also reflect a sense of steadiness or stability, such as regularity, orderliness, or routine.