Is 金口难开 an idiom, and if so what would be a suitable CC-CEDICT definition? I stumbled upon 金口难开, and I think it's a 成语.  I think it describes people who are pretentious (金口 = gold mouth), which makes it hard for them to speak (难开 = difficult to open).

Examples:


  
  家长怎么教宝宝都是金口难开，多半是少做了这些事[src]
  微信聊天，金口难开的女人无非有三个心理,摸准后她对你念念不忘 [src]
  金口难开，绝不会认错的星座! [src]
  


Question: Is 金口难开 an idiom, and if so what would be a suitable CC-CEDICT definition?

Here's my partial CC-CEDICT definition (which I'm not very confident about):

金口难开 金口難開 [jin1 kou3 nan2 kai1] /lit. a gold mouth is hard to open (idiom)/fig. to be too pretentious for words/


which is modified from a related definition:

羞口難開 羞口难开 [xiu1 kou3 nan2 kai1] /to be too embarrassed for words (idiom)/




PS: CC-CEDICT definitions need to be high-quality (they're used in dictionaries all over the world).  The whole dictionary is free to download.  Submissions are reviewed prior to modifying the database.  They have a specific syntax, e.g.: 中國 中国 [Zhong1 guo2] /China/Middle Kingdom/
金口難開
..... 後來，便有了「金口難開」這個成語，表示：嘴巴像金子一樣珍貴，不輕易張口用來說話；形容一個人沉默寡言、不愛說話。

Base on the story, 金口難開  originally describe &quot;someone value his own words like gold, do not open his mouth to speak unless it is necessary&quot; ; Now it is used to describe &quot;someone being reticent; a man of few words&quot;

金口 = golden mouth (valuable speech)

難開 = 難得打開 (rarely open)