The Illunse word for rust is rugorm. Similar Rugori is the name of a place in Burundi.
This word is a mixture of the Old English word for rust which is óm (also sinderóm) and rúst (rust, moral canker), and the Latin word for rust which is ferrugo (iron-rust; color of iron rust, dusky color) also rubigo (rust; mildew, blight; a foul deposit in the mouth).
rugormas : rusts
The Illunse word for rusts (noun) is rugormas. (I probably won't use this, but it'll help with declension)
Rusts in Latin is ferrugines. Rusts in Old English is ómas also rústas.