עמם

Abarim Publications' online Biblical Hebrew Dictionary

Scholars declare that there are two separate roots of the form עמם ('mm) in the Bible, but here at Abarim Publications we see no reason to see two:

עמם I

The assumed root עמם ('mm) isn't used in the Bible, so we don't know what it might have meant. But cognate verbs mean to be comprehensive or include. And it yields some derivatives that have the common meaning of togetherness (which leads some scholars to believe that it might be kindred to the root אמם ('mm), from whence stems the word אמה ('umma), meaning tribe or people):

The preposition עם ('im), meaning 'with' in a wide variety of senses. This particle has the exact same meaning as את ('et II).
The word מעם (me'im), meaning from, with or beside in a wide variety of senses;
The feminine juxtaposition עמה ('umma), meaning against, beside.

But our root also yields the following, less abstract words:

The masculine noun עם ('am), meaning a people in ways ranging from pretty much all mankind (Genesis 11:6) to a specific nation (Exodus 1:20) to the population of a town (Genesis 19:4). It sometimes occurs to differentiate between common folks and their leader (Leviticus 4:27), or to indicate people in general (Genesis 50:20) or simply general public, as in Jeremiah 17:19, where the prophet speaks of the Gate of the People.
The masculine noun עם ('am), meaning (paternal) kinsman. This word occurs mostly in plural, and is commonly translated simply with people or my people (Genesis 49:29, Numbers 27:13).

The word עם ('am) suffixed with the letter yod forms the compound עמי (ami) meaning either my people (kinsman), or people (kinsman) of.

עמם II

The verb עמם ('amam) means to darken or dim, and figuratively: to make secret. It occurs two or three times: Ezekiel 28:3, (and perhaps Ezekiel 31:8) and Lamentations 4:1. This verb obviously relates to the previous one in that one keeps a secret to oneself or to one's own people.