Mutual.—Does not mean common, but reciprocal. “We may have a common  friend, but a mutual  dislike”; that is, a dislike for each other.

mutual , common : These words are often confounded and have been so by writers of correct English. Mutual implies interchange; common belonging to more than two persons. Before the middle of the eighteenth century, mutual had two meanings: “joint” or “common,” and “reciprocal.” When Dr. Samuel Johnson published his great dictionary he gave it but one meaning, that of reciprocal, and, his authority as a scholar having grown so great, this meaning became considered the only one which might be correctly given to the word. “Mutual,” says Crabb, “supposes a sameness in condition at the same time; reciprocal supposes an alternation or succession of returns.” Thus we properly speak of “our common country, mutual affection, reciprocal obligations.” While mutual applies to the acts and opinions of persons, and therefore to what is personal, it is not applicable to persons. Macaulay condemned the phrase “mutual friend” as a low vulgarism. A “common friend” is certainly more accurate but unfortunately carries with it the disagreeable idea of inferiority, and probably for this reason is seldom or never used. There is authority of such prolific writers as Scott and Dickens for “mutual friend,” but the rapidity with which they wrote their books may suggest that they paid little heed to such refinements of language as did Macaulay. Yet centuries of English literature authorize the employment of mutual in the sense of joint or common. On the other hand, the very strong disapproval with which this and like uses of mutual are regarded by many writers of good taste may not unreasonably be considered as sufficient ground for avoiding mutual friend and kindred expressions. “Mutual friends,” says Phelps, “would not be accurate” meaning that two persons are friends each to the other.