Possessive + 朋友 / Adjective + 朋友
朋友 (péngyou) means "friend" and is the standard word for referring to friends in Chinese. It can be modified with adjectives or possessives, such as 好朋友 (good friend) or 我的朋友 (my friend). It is also used in broader social contexts, such as 男朋友 (boyfriend) and 女朋友 (girlfriend).
他是我最好的朋友,我们认识十年了。
Tā shì wǒ zuì hǎo de péngyǒu, wǒmen rènshi shí nián le.
He is my best friend; we've known each other for ten years.
周末我要和朋友一起去爬山。
Zhōumò wǒ yào hé péngyǒu yīqǐ qù páshān.
I'm going hiking with friends this weekend.
她交了一个新朋友,是隔壁班的同学。
Tā jiāo le yī gè xīn péngyǒu, shì gébì bān de tóngxué.
She made a new friend — a classmate from the next class over.