The word 'disregardance' is not very common and is not often used in everyday language. However, there are a few synonyms for the word that can be used interchangeably. The word 'neglect' can be used instead of disregardance, and it has more of an active connotation, indicating that someone deliberately ignored or overlooked something. 'Indifference' is another synonym that is often used to describe a disinterest or apathy towards something. 'Dismissal' is used to suggest that something has been pushed aside or rejected as important without much thought. 'Disrespect' is another synonym that can be used to suggest that someone hasn't given proper attention or consideration to something.