The answer to the crossword question is the word “UPON“. The clue provides three words: “follow“, “sneak“, and “check“, and requests a word that can follow all three words. The word “UPON” fits this criteria, as it is a preposition that can be used in a variety of contexts. In this case, it is being used to indicate a connection or proximity to the action of following, sneaking, or checking. Therefore, the answer to the crossword question is the word “UPON“.