Three of the following four words are alike in a certain way and one is different. Pick the odd word out.

we have to find the odd one out from the given options. As per the question the options 2,3 and 4 all have same meaning, 

valediction: process of saying goodbye similar to closing

cessation; process of ending

closure; means closing of something 

whereas option 1 is intermission means interval or recess between parts of a performance so it doesn't means the complete ending hence it will be different from the rest.