Vague
Vague
A word (or the idea or notion associated with it) is vague if the meaning is so far not fixed that there are cases in which its application is in principle indeterminate — although there may be other cases in which the application is quite definite. Thus longevity is vague because, although a man who dies at sixty certainly does not possess the characteristic of longevity and one who lives to be ninety certainly does, there is doubt about a man who dies at seventy-five. On the other hand, octogenarian is not vague, because the precise moment at which a man becomes an octogenarian may (at least in principle) be determined. Of course, the vagueness of longevity might be removed by specifying exactly at what age longevity begins, but the meaning of the word would then have been changed. (See further the article Relative.).
Similarly a criterion or test, a convention, a rule, a command is vague if there are cases in which it is in principle indeterminate what the result of the test is, or whether the convention has been followed, or whether the rule or command has been obeyed. — A.C. `