Sadaejuui (lit. "thing-big-ism", meaning: "serving-the-Great ideology"; Hangul: 사대주의, Hanja: 事大主義, ) is a largely pejorative Korean term which evolved in the mid-20th century  from a more widely used historical concept.

The contemporary term sadaejuui was derived from the Chinese shi da (Korean, sadae) as used by the philosopher, Mencius.
 Sadae literally means "dealing with the great" or "serving the great" and interpreted as "Loving and admiring the great and powerful".
Juui means "ideology" and it is conventionally translated as "-ism."
In other words, sadaejuui is a compound-word composed of sadae + juui.

Etymology
The term "sadaejuui" was invented by early 20th century Korean nationalists.  The antecedents of this modern term is the historic term "sadae" (), which comes from the word  in Mencius's () book,  which means "service to the great by the small" or "a small kingdom accommodates a large."

 
 

Mencius - Liang Hui Wang II

Overview
Sadaejuui conflates an attitude of subservience with the political realism which accompanies the prudent recognition of greater power.  Sadae describes a foreign policy characterized by the various ways a weaker nation-state such as Korea acknowledges the strength of a greater power such as China. Sadae is made manifest in the actions of the weaker nation-state as it conveys goodwill and respect through its envoys.

The utility of the sadae concept in Korea was recognized from the period of Three Kingdoms of Korea to 1897; and it is demonstrated in the relationship of mid-Joseon Korea towards the Ming dynasty of China. Joseon made every effort to maintain a friendly relationship with Beijing for reasons having to do with both realpolitik and an idealized Confucian worldview in which China is perceived as the center of a Confucian moral universe.

The kingdom of Joseon accepted its place in a Sinocentristic world order. The Joseon foreign policy was organized around maintaining stable Joseon–Chinese relations in the period from 1392 through 1910. It contrasts with limited trade relationships or kyorin diplomacy (교린정책/交隣政策; lit. "neighborly relations") in regard to Joseon-Japanese relations in this period.

The concept of sadaejuui was central in the writings of polemicist Shin Chaeho. His ideas and voice became prominent features of Korean nationalism.  Sin is known for having argued that the sadaejuui inherent in Confucian historiography served 
 to devalue the ethnic origins of the Korean people and state 
 to subjugate Korean history within a Confucian interpretive framework 
His revisionist writings sought to deny the relevance of sadae as an important element of Korean history.

See also 
 Tribute
 Samguk Sagi
 Gyorin
 Analogous concepts:
 West British
 Little Russian
 Cultural cringe

Notes

References
 Alford, C. Fred. (1999). Think no evil: Korean values in the age of globalization. Ithaca: Cornell University Press. ;  OCLC 247000674
 Armstrong, Charles K. (2007). The Koreas. London: CRC Press. ; ;  OCLC 71808039
 Kang, Etsuko Hae-jin. (1997). Diplomacy and Ideology in Japanese-Korean Relations: from the Fifteenth to the Eighteenth Century. Basingstoke, Hampshire; Macmillan. ;
 Levinson, David and Karen Christensen. (2002). Encyclopedia of Modern Asia. New York: Charles Scribner's Sons. ; 
 Mansourov, Alexandre Y. "Will Flowers Bloom without Fragrance? Korean-Chinese Relations," Harvard Asia Quarterly (Spring 2009).
 Pratt, Keith L., Richard Rutt, and James Hoare. (1999). Korea: a historical and cultural dictionary, Richmond: Curzon Press. ; ;  OCLC 245844259
 Robinson, Michael. (1984) "National Identity and the Thought of Sin Ch'ae-ho: Sadaejuüi and Chuch'e in History and Politics." Journal of Korean Studies 5: 121–142.	
 Robinson, Michael. (1988). Cultural Nationalism in Colonial Korea, 1920–1925.'' Seattle: University of Washington Press. ;  OCLC 18106164

 
Political theories
Korean philosophy
Ideologies
Korean Confucianism