Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
* mŏdimpĕrātor, ōris, m. [for modi imperator], the president or chairman of a convivial party, who prescribes the quantity to be drunk (the magister bibendi, the Greek συμποσίαρχος): potandi modimperatores, Varr. ap. Non. 142, 7.