昔

阿昔洛韦

ā xī luò wéi

aciclovir (also spelled acyclovir), antiviral drug

今不如昔

jīn bù rú xī

things are not as good as they used to be

今昔

jīn xī

past and present

今非昔比

jīn fēi xī bǐ

(idiom) things are very different now; times have changed

修昔底德

xiū xī dǐ dé

Thucydides (c. 455 - c. 400 BC), Greek historian, author of the History of the Peloponnesian War

修昔底德陷阱

xiū xī dǐ dé xiàn jǐng

Thucydides trap (theory that war results when a dominant established power fears the rise of a rival power)

古昔

gǔ xī

(literary) ancient times

奶昔

nǎi xī

milkshake (Note: 昔[xi1] is loaned from English "shake" via Cantonese 昔, pr. sik1)

宿昔

sù xī

formerly

往昔

wǎng xī

the past

昔年

xī nián

former years

昔日

xī rì

former days