The option that does not belong in this list is: Grass.
What is an odd word?
An odd word is a word whose basic features differ from the other words in a group.
In the list provided above, Grass can be considered the odd word because the sound by the double "ss" has more stress than the syllables at the end of the other words.
Learn more about syllables here:
https://brainly.com/question/1514007
