ko ‧ sher /ˈkəʊʃə $ ˈkoʊʃər/ BrE AmE adjective
[ Date: 1800-1900 ; Language: Yiddish ; Origin: Hebrew kasher 'fit, suitable' ]
1 .
a) kosher food is prepared according to Jewish law
b) kosher restaurants or shops sell food prepared in this way
2 . informal something that is kosher is honest, legal, or really what it is claimed to be:
Are you sure this offer is kosher?