Definition of overpost:
(v) :
To post too much or too often.
(v) :
(computing) To breach security by overwriting data that is not intended for user input.
(n) :
(accounting) An entry that has been posted more than once to a journal.
(v) :
(cartography) To print a text label or other graphic feature on top of another symbol.
(v) :
To place a poster so that it covers all or part of another poster.
(v) :
To pass over swiftly, as if by post.