Alright kiddies, there are two definitions for this.

1) In baseball, this refers to the superstition that a rookie's second year will be a bad one, i.e. he gets injured, plays a horrible season, or the team falls apart on account of his playing style.

2) In college, it refers to the time when classes are getting much harder, sometimes even the harder than the following years in an undergraduate program. It can also refer to the student changing his/her major and having a hard time with it at first.
1) There are too many to list, check the stats at www.mlb.com

2) Little Billy suffered the Sophomore Jinx when he broke down working on a Rigid Body Mechanics assignment. He's now an Anthropology major.
by Matt August 18, 2005
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An attempt to jinx your opponent by predicting doom and failure for your own team, saving face in the process should you lose, and allowing you to be incredibly smug in victory, thereby producing the anti-jinx. Typically seen when a team is a favourite, and most often used by Man Utd fans.
"Manchester United v Barcelona ECL SF2L – Tuesday…climaxing in the inevitable 1-1 draw."

This would be your anti-jinx.
by StanleyDonwood April 29, 2008
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when 2 people same the same thing at the same time, one person gets jinxed
Person #1 is "personal jinxed" when they say the same thing at the same exact time as Person #2. Person #2 then yells "JINX, PERSONAL JINX" to jinx Person #1. Then, Person #1 cannot speak until Person #2 says their name.
by lee money November 14, 2007
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When the same word or phrase is uttered in unison by three individuals. The first member to shout "Triple Jinx!" is the winner. The two losers must then sacrifice their first-born child.
Tyler, Ryan, and Dave all exclaimed, "Nice tits, bitch!" "Triple Jinx!" Dave replied. Tyler and Ryan are no longer parents.
by rainbow_reekris October 14, 2011
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When you compliment an opponent and admit defeat prior to the competition taking place.
John Hein “reverse jinxedmarble mouth JD right before their Fantasy Football matchup.
by "Anthony" from Chicago October 5, 2011
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2 or more people sending the same emoticon to each other at the same time
My friend and I sent eachother smiley emoticons simultaneously and she emoti-jinxed me, so I can't text until she texts me first.
by mplsbb January 8, 2014
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When two people get a text message simultaneously. The person who fails to say "Jinx text" first becomes Jinxed. This person can no longer speak until the Jinxer or one of the witnesses to the jinx says the name of the jinxed person.
(two text messages come in at the same time)

Steve: Jinx text!

Witnesses: OHHHHHH
by LukeyLuke December 22, 2012
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