In forum parlance, it means rushing to the aid of another poster for whatever reason. An accusation typically reserved for when a poster is being hammered by another poster(s) and the accused leaps in to defend them, usually without thinking things through as to why the person is being attacked.
Poster A: <Says something unfunny>
Poster B: Shut up, douche.
White Knight: Hey, leave him alone. Why are you all ganging up on him?
Poster B: Quite white knighting, douche.
by Boojoorooroo December 4, 2007
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A guy that sells out his own male gender to earn some extra " brownie " points with the ladies

Or a guy that will pretty much do everything a girl tells them..
Jack: " Hey hey what the fuck man, I'm the victim here, Sally pushed me!

Bouncer Mcgregory: Thats not what I heard, Sally said you were bothering her, I'm kicking your punk ass out the club

Jack: WAIT! Are you even gonna hear me out?! Fuck I'm not going anywhere without my lawyer!

Bouncer Mcgregory: No whatever Sally says counts, we need the hot girls here to attract more male customers. ( yes I did see Sally push you and spill her drink on your shirt, but I'm have to kick you out because I want to get into her panties tonight, sorry Jack your a good man, but its everyman for himself.. )

Mary: Ian was such a creep today, he shook my hand the wrong way

Bob: Woah, yea he is such a creep, that guy is some big ass loser. Your right. ( hoping to earn some points to get with Mary )

Bob: ( muahahaha, I'm such a white knight in shining armor! I am so bedding Mary )
by Emperor of West September 5, 2012
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1. A fake feminist who uses the language to appear woke.

2. A predator who preys specifically on trauma victims while feeding his own savior complex.
White knights are more dangerous than they appear.

He was playing the white knight til he assaulted her.

Sampson pretends to be a white knight to exploit the psychological impact of already existing trauma.
by Clearlyclarity July 31, 2020
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Standing up for someone or some thing, not in order to defend or help, but to make yourself look good.

Typically used by males, who have a rudimentary understanding of feminism and equality topics, using trendy words and expressions aimed to "sound good".
"If you don't know women who have been sexually abused it's because they don't trust you enough to tell you about it."
- Written by a white knight infamous for mistreating women.

or:

Girl is having argument with Boy 1 online, all civil.
Boy 2 interrupts/intervenes:
Boy 2: You are doing exactly what makes women uncomfortable around men.

Boy 1: Why are you White Knighting, bro?
by PH Berg September 29, 2018
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Defending someone who does not wish to be defended.
Scenario A:

Man: "Women should have equal pay for equal work!"
Woman:"We already do for the most part. Stop white knighting for us."

Scenario B:
Joe: "Wow, Susan, you're such a bitch, lol."
Jeff: "Take that back, Joe! Susan is a wonderful person."
Susan: "God, Jeff, he was just joking. Stop white knighting for me."
by Ike Moon the Nautical Bunny November 5, 2017
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White Knighting typically occurs when their are two men and one girl. White Knighting is easy to spot and very annoying when you are trying to get laid with a crappy wingman.

White Knighting is when one man is trying to get a girl into his bed while in the same area as his friend, his friend (if he is a White Knight) will typically attempt to disperse the conversation by presenting his chivalrous words such as: "Have some respect for women, Johnny" or "Miss, he's just trying to get laid" while simultaneously attempting to get laid himself by showing respect to the women. A White Knight will never act chivalrous when he is not around another guy.
Jim: Hey babe, you wanna go back to my place? I'll make you some food.
Lancelot: Jim, your just trying to sleep with her, I see this every time we go out
Girl: Excuse me? I'm not a slut. (leaves)
Jim: What the hell Lancelot, quit your White Knighting, I was about to get laid.
Lancelot: Dude I know! We should totally go out again tomorrow! I'm about to get that girls number, she's totally into me.
by Lord_Edward October 27, 2009
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a dude who supplicates too hard and probably has a small winky.

can be seen shaving with gillette and voting for hillary due to her gender alone
white knight: can i buy you a drink m’lady?

white knite: we need a woman presidannnt

white knigt: gosh golly i love my gillette razor. it always reminds me to check my male privilege
by jarlin dando March 14, 2019
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