Grandisonian UK /ˌɡɹæn.dɪˈsəʊ.ni.ən/US /ˌɡɹæn.dəˈsoʊ.ni.ən/ adjective1 •scrupulously moral and chivalrous, like the fictional Sir Charles Grandison in The History of Sir Charles Grandison (1753), an epistolary novel by Samuel Richardson. formsmore Grandisonian · most Grandisonian