one word teacher ❍ 宝玉听了，不觉洞开心意，笑道：“该死，该死！眼前现成的句子竟想不到。姐姐真是 ‘一字师’ 了！”(《红楼梦》210) The scales fell from Baoyu’s eyes. ‘Good gracious,how stupid of me! The words are there ready-made and I didn’t think of them! I shall have to call you my “One Word Teacher，” …’
一字之师yī zì zhī shī
改正一个字的老师。the teacher who correct one word of sb.’s articles, one word teacher