digbicks:

T O S K A, Lisa Sorgini

“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.”

- Vladimir Nabokov