プログレッシブ和英中辞典(第4版)の解説
あくゆう【悪友】
an undesirable friend；〔総称〕bad company
悪友と交わる
keep bad company
最近悪友ができたらしい
He seems to have fallen 「into bad company [in with a bad crowd] recently.
彼は高校時代からの悪友だ
((親友の意味で)) He and I have been good buddies since our high school days.