Is "missing person" considered a compound noun?

In the phrase missing person, is the whole phrase a compound noun or would missing be considered an adjective that modifies person? It seems like in many situations when it is used with other adjectives, missing is not treated as an adjective. In addition, I have seen the phrase pluralized as missing persons rather than missing people, which makes it seem like the phrase is viewed as one whole word.

Solution 1:

The difference between missing persons and missing people would be that missing persons means that the individuals that are considered here as persons are missing. Where it shows individuality. But missing people is more like a group of people missing.

Hence I would say that "Missing person" would not be considered as a phrase and "Missing" here would be considered as an adjective.

Solution 2:

Some dictionaries (OALD, Cambridge, Collins) have entries for missing person as a noun. Consequently, missing is not considered an adjective here.

According to these dictionaries, the correct plural form is missing persons.