Monmouther UK /ˈmɒnməθə(ɹ)/US /ˈmɒnməθɚ/adjective 1noun 1forms 1 adjective1 •(rare) Of, from, or related to (one of the various places called) Monmouth. noun1 •(rare) A person from (one of the various places called) Monmouth. formsMonmouthers