"strange" (compare other compounds such as hentai (變體, lit. 'unusual form') as in hentaigana (變體假名), and henkaku (變格, lit. 'unusual style') as in henkaku...

Hentaigana 変体仮名 変体がな 變體假名 變體がな itaigana (異体仮名) Script type Syllabary Time period c. 800 – 1900 CE; minor use at present Languages Japanese Related scripts...