The story
Like scrawny and scrannel, to an old root for drying out, such as Old English scrinian (“to dry”), potentially borrowed from North Germanic; compare cognate Swedish skranig, skranglig, skral, skran, Norwegian skran, Danish skrån (“scrawny, meager, dry, barren”). Also Norwegian skrann, related to skrinn, Swedish skrinn, skrin, from Old Swedish skrinder, to an Old Norse *skrindr (“meager, emaciated, thin”); see also English scrunt; potentially related to Lithuanian skrèsti (“getting scabby”). Also see Breton krina (“to dry”).
Etymology from Wiktionary, CC BY-SA 4.0.