hoping against hope; desperately hoping; as a last hope
An idiomatic expression describing a situation where one clings to even the slightest, most unreliable hope, like a drowning person grasping at a straw. Often used adverbially to modify verbs of seeking, asking, or relying.
Hoping against hope, he believed that information.
As a last hope, I tried that treatment.
Standard kanji spelling using すがる in kana; the most common written form.
Variant with the kanji 縋る for すがる; less common but still encountered.
From the image of a drowning person grasping at even a floating straw (藁). The phrase 藁にもすがる (to cling even to straw) is combined with 思い (feeling) and the particle で to form an adverbial expression.