Load-bearing wall or not?

[Magnus_R]

I'm in the process of building a wardrobe for a bedroom and encountered a bit of an issue. I want to tear down a wall, and when I exposed the wall, I became unsure if it might be load-bearing. The wall is built with tongue-and-groove 45x170 that extends from the ceiling down through the floor (as it appears). The wall is at a right angle to the attic's floor joists, which made me even more skeptical.

There doesn't seem to be any significant load on the boards as they flex when I tap them lightly.

There are already cut-out "wardrobes" in other parts of the wall.

I am attaching drawings and hope someone can offer some wise insights.

The images are shown in the following order:
2nd floor (where the wall is)
1st floor
Basement
Lower part of the wall towards the floor
Upper part of the wall towards the ceiling

 

[anaitis]

Timber with a thickness of 45 mm can almost never be load-bearing in the type of construction you have.

 

[injonil]

Isn't it? A 45mm thick tongued and grooved wall is what is called a plank wall and can be used as a load-bearing wall for an entire house, right? That's how my house is built, from '39.

 

[1Runner]

Wait a minute, was it the tongue or the wall that was 45?
45 mm wall sounds on the thin side.
If you want to frame with some bearing capacity, I haven't seen smaller dimensions than 45 x 70

 

[injonil]

What ts describes is a wall made of shiplap planks, known as a plank wall. Common in houses from the late 30s and into the 40s. They are completely load-bearing.