1: The condition or quality of being empty.
2: Exhaustion, as from lack of nourishment.
3: Lack of vitality or spirit.
 "The problem that faces British universities is not that they have become fat and lazy, but that they have been starved beyond lean efficiency into inanition." -- John Sutherland, "A contest that no one can really win," The Guardian, August 14, 2000
 "Even without, or before, revolution or foreign invasion, states can decline of their own inanition." -- Harold Perkin, "The rise and fall of empires: the role of surplus extraction," History Today, April 2002
 "Sadly, though not surprisingly, convention speeches designed to rouse voters from their indifference only exacerbate the country's inanition." -- Thomas J. Mccarthy, "This year's national party meetings displayed poll-itics as usual," America, September 9, 2000
Inanition derives from Latin inanitio, "emptiness," from inanire, "to make empty," from inanis, "empty." It is related to inane, "lacking sense or intelligence; pointless."
That bad case of the Blah that I get from time to time has a name. It's called "inanition".