Definition

1. Adjective:
   • Stupid, foolish, idiotic: "ngu si" describes a person who lacks intelligence, understanding, or common sense; who is slow-witted or acts in a senseless manner.
   • Ignorant, simple-minded: It can also refer to a state of profound ignorance or a lack of knowledge, often implying a naive simplicity.

Usage Examples

• Adjective:
  • Hắn ta hành động thật ngu si. (He acted really stupidly.)
  • Đừng có ngu si mà tin vào lời hứa hão huyền đó. (Don't be foolish enough to believe that empty promise.)
  • Cái nhìn ngu si trên mặt nó khiến tôi thất vọng. (The stupid look on his face made me disappointed.)

Advanced Usage

• "ngu si hưởng thái bình": This is a Vietnamese idiom, equivalent to the English proverb "Ignorance is bliss." It suggests that sometimes not knowing the truth or being unaware of problems leads to a happier, more peaceful life.
  • Đôi khi, ngu si hưởng thái bình cũng là một cách sống. (Sometimes, ignorance is bliss is also a way of life.)

Variants and Related Words

• Ngu (adj): Stupid, foolish. (A simpler, more common synonym).
• Ngu ngốc (adj): Foolish, silly. (A close synonym, often used interchangeably).
• Đần độn (adj): Mentally slow, dull-witted. (Emphasizes a lack of mental acuity).
• Khờ khạo (adj): Simple-minded, naive. (Often with a less harsh, more pitiful connotation).

Synonyms

• Ngu xuẩn (adj): Stupid, imbecilic.
• Dại dột (adj): Foolish, unwise (often regarding a specific action).
• Ngốc nghếch (adj): Silly, goofy.

Related Idioms

• Ngu si hưởng thái bình: Ignorance is bliss. (As explained above).
• Khôn nhà dại chợ: Literally "smart at home, foolish at the market." Means someone who acts confidently in familiar settings but is clumsy or foolish in public or new situations. It shares the theme of foolish behavior.

1. Thick-headed
   • Ngu si hưởng thái bình
     Ignorance is bliss; the fools will meet with luck