Only

唯一

wéiyī

(alone in a category)

唯一的

wéiyī de

(without sibling)

最好的

zuìhǎo de

(singularly superior; the best)

獨一無二的 /独一无二的

dúyīwú'èr de

(singularly superior; the best)

獨生的 /独生的

dúshēng de

(without sibling)

只

zhǐ

(no more than)

只有

zhǐyǒu

(without others or anything further; exclusively)

只有

zhǐyǒu

(no more than)

惟獨 /惟独

wéidú

(without others or anything further; exclusively)