弟弟
dì di
younger brother
CL:個|个[ge4],位[wei4]
younger brother (弟) + younger brother (弟) = little bro
弟 originally depicted a cord wound around a stake, evoking the idea of rank and order among siblings. The repeated character simply doubles the word into an affectionate, familiar form — as Chinese often does for family terms.
我有一个弟弟，他今年八岁。
wǒ yǒu yí gè dì di，tā jīn nián bā suì。
I have a younger brother; he is eight years old this year.
我弟弟比我小五岁，他喜欢踢足球。
wǒ dì di bǐ wǒ xiǎo wǔ suì，tā xǐ huān tī zú qiú。
My younger brother is five years younger than me; he likes to play soccer.