Having friends can be both a blessing and a curse. They have the ability to support you through times of crisis and scold you when boundaries have been overstepped. However, it is normally to have various groups of friends that represent different aspects of life. Sometimes, when these pals are introduced to other acquaintances, it can be hard to sufficiently describe your relationship.
Here's how to do it in Chinese:
男/女朋友 (nán/nǚpéngyǒu) boy/girlfriend
While not entirely within the realm of "friend", similarities still remain—plus it has that buzzword embedded into it.
The use is fairly simple and straightforward. It should be employed to induce feelings jealousy and derision amongst other family and friends.
Example:
爸妈,这是我女朋友.
Bàmā, zhè she wǒ nǚpéngyǒu.
Mum, dad, this is my girlfriend.
哥们儿 (gēmenr) brother
Can be regarded as the male equivalent to 闺密. The conditions for use are exactly the same but simply with the genders reversed. The "er" sound at the end is added so the user is not embarrassed and to improve the sound.
Example:
晚上哥们儿一起踢球.
Wǎnshàng gēmenr yīqǐ tīqíu.
In the evening, the brothers are going to play soccer.
同学 (tóngxué) classmate
Many people go to school at one point during their lives. And during these times, friends are often made. 同学 is used when you need to refer to most of these people. It is normally used to refer to classmates or those that were in the same grade as the user.
Example:
我们明天同学聚会.
Wǒmen míngtiān tóngxué jùhuì.
Tomorrow, we are having a class reunion.
发小 (fàxiǎo) childhood friend
Remember when you were four years-old and running around the backyard buck-naked, without a care in the world? There was that other kid, he/she used to come round all the time to play in your sandpit. You became fast friends and through the years, have remain on a close level. Even now, after a day toiling in the office of your state-run company, you find time to video chat with that childhood friend.
That's your 发小.
Example:
我四岁的时候认识我发小.
Wǒ sì suì de shehòu rènshì wǒ fàxiǎo.
I met my childhood friend when I was four.