What does the idiom "Yellow streak" mean? [closed]

My question is and I would like to know that at one time frequently used the idiom "YELLOW STREAK" now rarely used. The Idiom is used regarding, CHINESE PEOPLE".What does the Idiom mean?

In which contexts this idiom can be used.it seems the meaning is critical and disrespectful. In English novels written by Somerset Maugham, these set of words are sometimes found. Can the set of words be used as Applause?

Solution 1:

A yellow streak, according to the OED (under "yellow, adj. and n."), is

colloquial (originally U.S.) a tendency towards cowardice (cf. sense A. 3b).

The first cited instance helpfully glosses the compound:

1892 Daily Picayune (New Orleans) 19 Sept. 3/1 They..said..that I could not hit hard, and that I had a ‘yellow streak’—meaning that I was afraid.

It is unclear why exactly yellow is associated with cowardice. Under A. 3b, the OED poses one possibility but admits uncertainty:

The colour yellow was already associated with treachery in the Middle Ages, as is seen (for example) in the frequency with which Judas Iscariot is represented in medieval art as wearing yellow or having a yellow beard (cf. Judas-coloured adj. at Judas n. Compounds 2a); however, the origin of the specific association of the colour with cowardice, which seems to have arisen in American contexts in the later 19th cent., is unclear.