freeloader: someone who takes advantage of the generosity of others
borrower: someone who receives something on the promise to return it or its equivalent
erythroblastosis fetalis: severe anemia in newborn babies; the result of Rh incompatibility between maternal and fetal blood; typically occurs when the child of an Rh-negative mother inherits Rh-positive blood from the father; can be diagnosed before birth by amniocentesis