It seems I’m a bit obssessed with synonyms.
Just for fun, here is a list of 31 ways to say “idiot” in Mandarin, ranging from most common to least common.
1. 白痴 báichī – An idiot. Can also mean idiocy as a disease.
2. 傻子 shǎzi – Idiot. Less formal.
3. 呆子 dāizi – Same as 傻子 shǎzi.
4. 愚人 yúrén – Idiot in 书面语 shūmiànyǔ (formal/written language); literary register.
5. 蠢货 chǔnhuò – Idiot, a “stupid commodity”. Used as a term of abuse.
6. 蠢才 chǔncái – Same as 蠢货 chǔnhuò. Alternative form: 蠢材.
7. 傻瓜 shǎguā – Idiot, used either as a term of abuse or jokingly between friends. Literally, “dumb melon.”
8. 呆瓜 dāiguā – Same as 傻瓜 shǎguā.
9. 笨蛋 bèndàn – Idiot, as a term of abuse.
10. 二百五 èrbǎiwǔ – A simpleton. Slang. Literally, “two hundred and fifty” – have no idea why.
11. 蠢人 chǔnrén – Idiot.
12. 木头人 mùtourén – Idiot, specifically one who stares blankly, as if in a trance, or one who is slow in understanding. Dated.
13. 傻帽儿 / 傻帽 shǎmào[r] – Idiot or idiotic. Colloquial.
14. 草包 cǎobāo – Idiot. Literally, “straw bag”. Dated.
15. 脑残 nǎocán – Idiot. New and popular slang. Literally, “brain impairment.” Can also function as an adjective: “brain-dead”. Is often used to put-down the 富二代 fùèrdài – the supposedly idiotic children of wealthy families in China.
16. 饭桶 fàntǒng – A good-for-nothing – a “rice bucket” – that is, someone who can only eat but not doing anything of note.
17. 傻逼 shǎbī – Idiot. A popular new slang expression. Literally, “stupid cunt”. Probably derives from 牛逼 niúbī, “cow’s cunt”, another popular expression, which equates to “fucking awesome” in English. Appropriately vulgar, but extremely common. Alternative/polite form: 傻B.
18. 蠢驴 chǔnlǘ – Idiot. Literally, “stupid donkey.” Term of abuse.
19. 低能儿 dīnéngr – Idiot. Can also mean one who gets high marks in school but fails at life. Wenlin lists a third meaning as, “sb. with little or no ability in a certain area.”
20. 笨家伙 bènjiāhuo – “Stupid guy.”
21. 无知者 wúzhīzhě – Long-winded form of idiot – same as 愚人 yúrén.
22. 憨子 hānzi – Idiot. Rare, regional slang.
23. 笨瓜 bènguā – Same as 傻瓜 shǎguā and 呆瓜 dāiguā.
24. 笨贼 bènzéi – Idiot. Uncommon. Literally, “stupid burglar.”
25. 愚氓 yúméng – Idiot/fool. Uncommon.
26. 痴汉 chīhàn – Idiot/fool. Uncommon – probably another dictionary-only word.
27. 胸大无脑 xiōngdàwúnǎo – Not just an idiot, but a big-breasted bimbo. Slang.
28. 脑缺氧 nǎoquēyǎng – Literally, “brain lacks oxygen.” Refers not just to an idiot, but specifically one who can’t express oneself. You might say to such a person, 你脑子进水了 nǐ nǎozi jìnshuǐ le, meaning, “Your brain is flooded.”
29. 笨货 bènhuò – Idiot. Literally, “stupid commodity.”
30. 大傻个儿 / 大傻个 dàshǎgè[r] – Idiot. Northern slang, meaning, “big dumby.”
31. 笨伯 bènbó – Idiot. Uncommon. 书面语 shūmiànyǔ (formal/written language).