Used in response to questions when one simply cannot be bothered to, or simply cannot find the right words to answer. The word has numerous meanings and intents, thus meaning one must apreciate the TONE in which the word is spoken aswell as CONTEXT in order to correctly interpret the response.
Most often accompanied by a humble chin stroke and shoulder shrug. With careful use the word has the power to make one seem smart, however over use can have a reverse effect.
The true answer to the universe.
*Question; yo dude sup?
Response; Meh *
here meh can be taken to mean,
'I'm not doing anything'
'I'm not doing much but i cant be bothered to talk to you'
'I'm doing lots-don't have time to form a response'
'My life sucks but you don't realy need to know that'
'my fishy drowned'
'I ate too many jelly babies and now I am hyper'
'Fuck off and die bitch'