Interesting question. I've heard people use 'geek/nerd' and 'indoorsy' to describe 宅男、宅女。 I've also heard people use homeboy and homegirl. However, the strict/technical definition of homeboy/homegirl is: 1) close friend 2) gang member So you need to be careful when using it. You need to say the proper sentence. If you say: He is my homeboy. (close friend) The homeboy just did a drive by and shot 10 people at the birthday party. (Gang member) Homeboy over here never leaves his house! (indoorsy) Conclusion: Geek and nerd is possible, but many people who like to stay indoors do not necessarily have to be geeky or nerdy, so I don't like this term that much. Indoorsy is probably the most precise technical term, but this defintion is somewhat lacking in my opinion because there are a lot of characteristics that a 宅男、宅女 has that the term 'indoorsy' does not describe. For example: 宅男、宅女 are often associated as choosing to withdraw from social life to varying degrees. They often set their own sleep schedules, typically waking in the afternoon and going to bed early in the morning. For some (but NOT all), who are considered nerdy or geeky, their days are characterized by long spells of sleeping, while nighttime hours are spent watching TV, drawing, playing computer games, surfing the Internet, reading, listening to music, and other non-social activities. While such people favor indoor activities, most venture outdoors on occasion, though they prefer to do so at night. Therefore, I think the best way to describe such a person is to use the term 'homeboy/homegirl'. But additional context must be given in the sentence(s) stated. Because as I mentioned before, 'homeboy/homegirl' has other meanings.

indoorsy 是“宅”的意思，对应的是“outdoorsy”这个词，大多数字典上都有outdoorsy这个词。indoorsy是随时代所造出来的新词。 你可以说，I am not indoorsy.(详见美剧《生活大爆炸》第2季第11集）

geek, nerd. We don't distinguish between female geeks or male geeks