In relation to [this question](https://judaism.stackexchange.com/questions/76927/the-afflicted-poor-and-humble-a-reference-to-the-command-to-afflict-oneself-on), I would like to know why Vayikra 16:31 says *v'initem*, often translated as afflicting, cause if afflicting is about fasting then why isn't the word tzom צום used if this was what was meant by 'the Author'. 

Is it really about fasting or is fasting really included, what proof is there?