An intense, tormenting yearning.
An intense, tormenting yearning — a heartache that smoulders without let-up and seems to eat away at you.
Adds active torment and self-consumption to plain longing or yearning — it is yearning that wears you down (“gives no respite”). More acute and painful than the bittersweet, gentler saudade; where Sehnsucht reaches metaphysically toward an ideal, struggimento foregrounds the consuming ache itself. The vivid etymological image: the longing literally melts you.
From struggere “to melt, dissolve, consume” + -mento = “a melting / consuming.”
From the verb struggere “to melt, dissolve, consume” + -mento; struggere descends from Latin (Vulgar Latin sense “to melt, consume”).
The concrete literal sense (“melting,” e.g. of snow) is primary in Treccani; the figurative emotional sense developed from the metaphor of being “melted / consumed” by feeling, associated in Romantic-era usage with German Sehnsucht.
Romanticized on “untranslatable Italian” lists; in fact a normal literary/standard noun whose core (“consuming, tormenting longing”) is renderable in English. The Sehnsucht equivalence is a real comparison, not an exact identity.