The quality or state of being gummy; the degree to which something is sticky or adhesive.
From 'gummy' plus the abstract noun suffix '-ness,' which converts adjectives into nouns representing their qualities. This is one of the most productive suffixes in English.
The '-ness' suffix is so useful that English speakers can attach it to almost any adjective to create an abstract noun—we invented 'awkwardness' and 'saltiness' the same way we formed 'gumminess,' on the fly.
Complete word intelligence in one call. Free tier — 50 lookups/day.