Toska - noun /หtล-skษ/ - Russian word roughly translated as sadness, melancholia, lugubriousness. "No single word in English renders all the shades of toska. At its deepest and most painful, it is a sensation of great spiritual anguish, often without any specific cause. At less morbid levels it is a dull ache of the soul, a longing with nothing to long for, a sick pining, a vague restlessness, mental throes, yearning. In particular cases it may be the desire for somebody of something specific, nostalgia, love-sickness. At the lowest level it grades into ennui, boredom.
Vladimir NabokovWhatever his secret was, I have learnt one secret too, and namely: that the soul is but a manner of being - not a constant state - that any soul may be yours, if you find and follow its undulations. The hereafter may be the full ability of consciously living in any chosen soul, in any number of souls, all of them unconscious of their interchangeable burden.
Vladimir Nabokov