buddy哥们儿;

colleague同事/同僚;

confidante闺蜜/红颜知己(女性);

intimate至交;

mentor导师/指导者;

sworn brother结拜兄弟;

superior/boss上司/老板;

partner搭档;

couple情侣;

companion同伴;

pen pal笔友;

comrade-in-arms战友;

fellow-apprentice师兄弟;

bosom friend知心朋友