In the question, four words are given. Which of them will come in the last if they are arranged alphabetically as in a dictionary?

Rumour

If the words are arranged alphabetically, the order would be as follows: Rumanian, Rumbistious, Ruminate, Rumour

So, the answer is: Rumour

In order to understand how we came to this answer, we need to first understand the following example and then solve the above question accordingly.