to rub oil on skin: the everyday oiling of a body, not a ceremony.
This is the plain word for putting oil on skin. In a hot, dry country oil kept a body from cracking and left it looking and smelling cared for, so oiling yourself belonged with bathing and getting dressed. That fixed order shows up whenever someone steps back into ordinary life: David gets up off the ground, washes, oils himself, and changes his clothes. Naomi tells Ruth to do the same three things before she goes down to the threshing floor.
Because the oil was that ordinary, going without it said something. A person in mourning left it alone, which is why Joab tells the woman from Tekoa to put on mourning clothes and skip the oil, and why Daniel records that he used none for three weeks. The prophets turn the same habit into a threat: Deuteronomy promises olive trees across the whole land and still no oil to rub on, because the fruit will drop before it can be used, and Micah says much the same of a people who will tread out their olives and go without anyway.
The oiling can also be done to someone else, and there it is an act of care for a body that has been neglected. God bathes the abandoned child of Ezekiel's parable and then oils her. The northern leaders who send their Judean captives home clothe them, feed them, and oil them. In neither place does the oil give anyone a rank; it simply tends a body.
Keep this word apart from מָשַׁח, the verb for the anointing that sets a king, a priest, or a holy object apart for God. That one makes a person "an anointed one." This one just gets oil on skin.