you're lumber

[Yujan Chou]

The following is from a recap of the TV show Succession S4E8, and I was wondering what "lumber" means here.

So when Shiv comes at Greg, putting him in his place for trying to wrangle her away from the newscast set, he responds with, "< --- >I guess my only question would be if anything did come to pass in terms of you and he," – referring to Matsson. < ---- >

Shiv offers to refrain from pulling his innards out of his backside. "Go on, you're lumber. Keep your snout out."

< Edited to comply with 4-sentence limit on quotation (Rule 4). Cagey, moderator >

 

[PaulQ]

As I understand it, and as you should have mentioned, Shiv is of British descent. In BE, "lumber" = unwanted items, usually stored in the attic or a lumber room.

snout = nose - keep your snout out = don't interfere.

 

[Myridon]

The actress is Australian but the character is American. Regardless, it's an American TV show and that's not a British term that's known to me (and I watch a lot of British TV shows and movies). What's a lumber room?

 

[PaulQ]

The actress is Australian but the character is American.

Shiv’s parents are wealthy British aristocrat Caroline Collingwood and bullish businessman Logan Roy.

I'm a match to Shiv Roy from Succession.

What's a lumber room?

A room in a house where lumber is stored...

 

[Myridon]

I'm of British decent.. only 400 years ago. I don't think this family that has lived for all her life in America are going to be talking in British slang.

 

[PaulQ]

I'm of British decent.. only 400 years ago.

I'd have to see the papers...

British slang.

Ahem... Lumber is relatively high register... OED;

lumber, n.1
1.a. Disused articles of furniture and the like, which take up room inconveniently, or are removed to be out of the way; useless odds and ends.

 

[Myridon]

According to Wikipedia, the person she is speaking to is her father's grand-nephew so (hopefully) not related to her father's second wife at all. Neither he nor the American audience would recognize that use of lumber.

A room in a house where lumber is stored...

Now you're just being difficult.

 

[LVRBC]

It's junk that isn't quite junky enough to be thrown out yet, right? So a lumber room is where you keep it? Imagine having enough space in a house to dedicate a room to this, rather than just one shelf in a closet.
But, if this is an idiom in US-English, it's in a specialized jargon that I've never heard. Can it just be this character's idiolect?