To emphasize ItaloMonteCosta and oupajohn: The comparison between lair (English) and lar (Portuguese) lies in the etymology (roots of meanings) of the words – It cannot be used as a translation.
The historical meaning of lair in English was a resting place. In modern English it is a dwelling (living and resting) place of a monster, or a wild animal – mostly of a predator. As I search my brain, it seems that you would not use "lair" to describe a home of a person unless you wanted to specifically compare it to that of an animal. In Portuguese it might not be used as often as casa, but it certainly does not have the connotation of the home of an animal/monster.
Interesting you should bring that up. When I'm learning new languages and don't know a word I always try to imagine if it resembles a Latin or Greek root word, and I immediately thought of "lair" which can also be a "den" which is a safe often hidden home (now part of a home traditionally a man's lair, den, or "man cave") and the definition of some masculine animal's cave homes like a lion's lair and a wolf's den. Makes it easier to remember that this can be a "home."