gunk /gungk/ (informal)

1. Any unpleasant, dirty, sticky material
2. Any semi-solid, usu valueless, residue from a chemical process

• rust-resistant
• rusts
• rusty
• rusty-back
• rusty-backs
• rusty-coloured
• rusty nail
• rusty nails
• rusé
• rut
• Ruta
• rutabaga
• rutabagas
• Rutaceae
• rutaceous
• ruth
• Ruthene
• Ruthenian
• ruthenic
• ruthenious
• ruthenium
• rutheniums
• rutherford
• rutherfordium
• rutherfordiums