A yamin mun‘aqidah is an oath formed, under the relevant conditions, concerning a future action or abstention; expiation is discussed if it is breached. A yamin ghamus is a deliberately false oath, a grave wrong but not identical in legal character to the former.
This example is not an exhaustive treatment of all oath rulings. Its methodological point is that a specific literal meaning can define the scope of a ruling; one cannot simply broaden that scope by invoking an available secondary meaning.