"an eating" (akin to bibrosko, "to eat"), is used metaphorically to denote "rust" in Matthew 6:19,20 . See EAT , B, No. 1, FOOD, MEAT, MORSEL.
"poison," denotes "rust" in James 5:3 . See POISON.
an intensive form of ioo, "to poison" (akin to A, No. 2), strengthened by kata, "down," "to rust over," and in the Passive Voice, "to become rusted over," occurs in James 5:3 , RV, "are rusted" (AV, "are cankered"). Cp. gangraina, "a gangrene," 2 Timothy 2:17 , RV.