mer mer mer

-A noise one makes instead of a sigh.

-A noise one makes that indicates apathy towards whatever is occurring at the moment.

-A noise one makes when one is bored or uninterested.

-It can also be used as a response to something when there is no answer for it, or if you do not know the answer to it.

-It could also show ones agreement with another person when one is not in the correct mindset to answer with a word or sentence.