The present participle of a hypothetical verb 'cabble,' potentially meaning to fish for or prepare cabble (fish), though this is an extremely rare or archaic usage.
If from cabble, would follow the standard '-ing' participle formation, but the underlying verb is so obscure that the participle form is essentially historical or has virtually no modern usage.
The fact that we can form 'cabbling' grammatically (noun → verb → participle) shows how English's word-building rules are so systematic that we can create words that probably nobody has ever written or said—it's like grammatical creativity that expands beyond actual communication.
Complete word intelligence in one call. Free tier — 50 lookups/day.