Sour loser means when someone is angry about losing and doesn't take it well, taken from the phrase sour grape and is pretty similar to sore loser
by Crazy blue 0104 September 2, 2019
The origin of the word "sore loser". This much makes more sense than using the phrase with a "sore" in it. Sour comes from the phrase, "Sour grape". A big misconception of that figure of speech.
To whine or sour grape
To whine or sour grape
by Craig Thomson October 2, 2013