Synonyms for Excretion (same or very similar meaning)
WordNet sense 1 (waste matter (as urine or sweat but especially feces) discharged from the body):
excrement, excreta, body waste, excretory productWordNet sense 2 (the bodily process of discharging waste matter):
elimination, evacuation, excreting, voidingFrom the ODE community, based on WordNetadd/edit