loperamide Syllabification: (lo·per·a·mide)Pronunciation: /lōˈperəˌmīd/Definition of loperamide noun Medicine a synthetic drug of the opiate class that inhibits peristalsis and is used to treat diarrhea. Origin: 1970s: probably from (ch)lo(ro-) + (pi)per(idine) + amideloperamide in other Oxford dictionaries Definition of loperamide in the British & World English dictionary