Likely from the same vibe that inspired 'meh'. It's the abridged version of my original : fustigoodeehadeeha.
Basically -- 'meh', with delicate overtones of disingenuous appreciation.
And then, there's *'Tsvar' -- which fell out of popular usage when a former boss started using it ad nauseum.
He apparently had no creative capacities of his own. Sounded even sillier than me saying it -- and that's going some.
Tsvar: an exclamatory word or phrase; especially: a vague expletive -- poignantly ambiguous, with essence of caviar.
My rule of thumb is that if you simply cannot find the proper word you are looking for, particularly in written correspondence, just go ahead and make one up. Human language is so sophisticated that the large majority of people will understand the meaning behind your fabricated word even though they have never heard it before. Whether the meaning is indirectly implied by virtue of the words around it, OR, the word simply "sounds right," most people will get it. It's frustrageous when they do not however... but there are worst things, like a kick in the scruttocks.
I created the word "Sculptography" and use it to define my new medium which combines both sculpture and photography. I found out that others had used the term but were incorrect in their use of it so I quickly defined it in the only dictionary available to me at the time the Urban Dictionary.