to shut or close something, keeping what is outside out or what is inside in
The basic force of this word is the physical act of closing: a door swings shut, a gate is bolted, a wound is closed over. The thing doing the shutting can be a person (shutting a door behind them), God (shutting Noah into the ark, closing up Sarah's womb), or the object itself (scales locked tight, a gate that stays shut). What is shut may be an entrance, a body, or a city, the common thread is that access is blocked.
A specialized and frequent use appears in the Levitical quarantine laws: the priest "shuts up" the person with a suspicious skin condition for a period of isolation and observation. Here the word does not mean imprisonment but controlled separation, the person is confined to a space while the condition is assessed. The same logic governs Miriam's exclusion from the camp for seven days.
A third cluster uses one form of the word as a fixed expression for refined or pure gold: the "shut" or "enclosed" gold of the temple furnishings (1 Kings 6-7; 2 Chronicles 4; 9). This is likely the image of gold that has been sealed or worked into solid form, as opposed to raw ore or plating, the same root that closes a door here describes metal finished into a dense, enclosed mass.