Formal:
* 礼物 (lǐwù): This is the most common and formal way to say "gift". It's used in most situations.
Informal:
* 礼物 (lǐwù): Can also be used informally, but less common.
* 东西 (dōngxi): This literally means "thing" and is a more casual way of saying "gift".
* 送的 (sòng de): This means "something that is given" and is another casual option.
Example:
* 我给你准备了一份礼物。 (Wǒ gěi nǐ zhǔnbèi le yī fèn lǐwù.) - I prepared a gift for you. (Formal)
* 我送你东西。 (Wǒ sòng nǐ dōngxi.) - I'm giving you something. (Informal)
Tip: When in doubt, use 礼物 (lǐwù). It's always appropriate and polite.