I lack the proper terminology to research this subject, so I'm just posting it here and calling it underarmor. Also, that's not helping me google this one.

So far, I only see that long johns, certain shirts and pants, the stock B.O.S. uniform (red), and Vault suits cooperate with the adding-on of armor pieces. Am I missing out? Is there a list somewhere? Thanks.

- Army Clothes

- Military Clothes

- Leather

I never understood why this Game has no Vanilla Choice for using Clean Black Suit and single Raider Metal Armor Piece. Iam using a Mod right now and the Clipping between Suit and Armor doesnt look that bad. Actually its really cool looking.

The Wiki page has a pretty good list. This lists all of the different armor types first. Then the 'Clothing' section contains clothing that can be worn under armor. The 'Outfits' section contains clothing and unique armor that mostly can't be used with armor. Some of the outfits can be worn with just arm piece or just leg pieces.

http://fallout.wikia.com/wiki/Fallout_4_armor_and_clothing

http://fallout.wikia.com/wiki/Ballistic_weave

i think they just wanted to give you one underarmor for the most prevelant stat combos but thats it....there is no logic behind it (why for example undershirt + jeans cant be an underarmor etc.)....

but there is a mod that changes that which i think very useful (armorsmith extended) on the nexus