What's the masculine form of boudoir?

What's the word for a man's bedroom or private room -- as opposed to boudoir, which is a woman's bedroom or private room? If one doesn't exist in common English usage, what would be a French loanword? Or possibly a loanword from another language?


Solution 1:

A man cave (also called manspace), is often used for a man's private room.

As in,

I'm planning to turn the spare bedroom into a man cave.

Fortress of Solitude, a Superman reference, is also applicable.

As in,

If you're looking for Clark, he must be upstairs, in his fortress of solitude.

[Wikipedia]

Solution 2:

I retreat to my den:

noun

1.0 A wild mammal’s hidden home; a lair:
a female mink had set up her den there

1.1 informal A room or hideout where a person can go to relax or be private:

This expression is less colloquial than man cave, but it has the same connotations. It also has the benefit of masculine connotation with unisex denotation, just like boudoir has feminine connotations with a unisex denotation.