flavor is just that. Flavor. A full flavor has plenty of flavor. often it stands out as a recognizable flavor.
body is how strong a cigar is. how it makes you feel. how it reacts with your body.
to better understand body VS flavor you should do tests. Get yourself a cusano 18 double connecticut and a camacho diploma. I would say that both of these cigars are full flavor. however, the camacho diploma is full body where as the cusano is a mild to medium body.
smoke the cusano after lunch. smoke the diploma after dinner.
note how you feel after each one.
Body is better experienced, not discribed.