Body indicates the Monster's skin (or whatever...). For example, a Black Lion is a "Furry Animal" ("FA"). Common sense would suggest that a "furry animal" is vulnerable to fire but resistant to cold. Some creatures wear armor, in which case the armor is also listed, after a slash. For example, a Moor Boogey has "Tr/Ch", which means it has a troll-like skin, protected by chain armor.