What does the word 昳 mean? Can it be used in a name?

Do not use it as a name, it has a bad connotation!

Two words, two pronunciations, different meanings

dié,yì

[dié] (sun) to the west

[yì] 〔～丽〕beautiful

Other people pronounce it wrongly, and the meaning changes, so it’s better not to use it.