Definition of opponent for English Language Learners. : a person, group, etc., that is against something (such as an action, law, or system) : someone or something that does not want something to exist, be done, etc.
Generally, your first mortgage payment is due on the 1st day of the 2nd month following your closing date. For example, if you close in February, your first mortgage payment will be due on Aproil 1st. Generally speaking of course.
Usually, payments based on the income of the previous quarter are due on April 15, June 15, September 15 and January 15. But there are many rules about when and how much to pay on a quarterly basis, so you should consult your tax advisor or accountant to verify the schedule.