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.
So, your first mortgage payment is paid at the beginning of the first full month after closing and every month thereafter. Conversely, if you rent a home on June 1, for example, your rent would be due June 1 because it pays for the month of June in advance.