Usually used in the plural form, MILPs. This stands for Moms I'd Like to Punch, on analogy with the widely use MILF
(Mom I'd Like to Fuck). Specifically, MILPs are vacuous or insipid young stay-at-home moms that bore and irritate the more educated or sophisticated moms who are reduced to socializing with them for the children's sake.
I'd rather be at home reading Günter Grass, but there's no school today, so I had to take Finn and Olivia to the park and listen to a bunch of MILPs talk about soap operas and peanut allergies.