"Neckbeard" is a pejorative online term to describe a person who exhibits social awkwardness, underachievement, and pretentiousness.
It's a reference to the poor grooming and hygiene standards associated with these folks, and their facial hair in particular, which, according to the stereotype, is unkempt and extends down their neck.
This doesn't mean that every guy with man fur under his chin automatically becomes one. Plus, people's personalities are so nuanced that it's often impossible to make an accurate assessment of them from something they say on the internet.
However, it it does mean that if you are hateful towards others just because you need to mask your personal insecurity and a lack of self-confidence, you might end up on the subreddit 'Neckbeard' as punishment. Here are the ones who did.
#1 Sorry Ladies
Image credits: FruitsAreGoodForU
#2 "Stop Telling Me To Get A Job"
Image credits: RockyMntnView
#3 Oh S**t, He’s Gonna Take Legal Action!
Image credits: therattywoman
#4 I Just Can’t
Image credits: Zek0ri
#5 This Is What Comes To Your Head?
Image credits: antonio_dhanteras
#6 Dude, You Stink
Image credits: HungerLefty
#7 Stop Kissing M’ladys Hand
Image credits: anamezon2008
#8 Is That So Much To Ask??
Image credits: aethericallum
#9 Check Those Drives
Image credits: Aliascrenel22
#10 This Neckbeard Wants Kawaii Sharia Law
Image credits: No_Biscotti_7110
#11 Now That's True Love
Image credits: Rod-FM
#12 Neckbeard Found A “Girlfriend”
Image credits: NoMaskTilReparations
#13 Neckbeard Gets Pissed Because Unlike His Expectations, The Us Army Is Not All 80s Sylvester Stallon Clones
Image credits: R_Dey
#14 I Don't Think I've Ever Seen An Actual "Funny Meme" On That Shithole
Image credits: RustedAxe88
#15 Most Likely A Neccbeard
Image credits: JudithBurley
#16 Think About It
Image credits: ntlane2004
#17 Local Weaboo Upset About Japan Not Being Their Fantasyland
Image credits: crestren
#18 How Dare You Be Sad About People Making Deepfake Porn Of Yourself? Like, Grow Up!
Image credits: haley____
#19 He Only Watches The Most Cultured Anime
Image credits: Tiara1752
#20 Found On Twitter, Where Neckbeards Still Prey On Ukrainian Refugees
Image credits: LaFilleDuMoulinier
#21 Just Saw This And Figured It Belonged Here. Yikes. Comments Are Currently Ripping Him Apart
Image credits: LOVallie
#22 Who Hurt This Guy?
Image credits: RossPerot_1992
#23 Broski She Just Said She Had A Boyfriend
Image credits: BiBluejay-169
#24 Don't Know If This Has Been Posted Here
Image credits: Man-Spider_1301
#25 Local Man Fetishizes Students
Image credits: ele05944
#26 The Last Thing His Enemies See Before Filing A Police Report
Image credits: ntlane2004
#27 Incels On Twitter
Image credits: SkepticDrinker
#28 For Neckbeards Too
Image credits: sickboy2512
#29 Saw This On Askmen Today… Yikes
Image credits: xxyy123123
#30 “Accidentally” Dressed In The Fully Identical Costume Of An Anime Character
Image credits: FenrirIII
#31 Hot Tub Offer
Image credits: Twelve-Majestic-Lies
#32 "Basically I'm Looking For Me, But A Girl"
Image credits: 42words
#33 Neckbeard Movie Review
Image credits: DORGS_BigToe
#34 Which Circle Of The Infernal Spiral Does This Person Come From
Image credits: Major_Ghoul
#35 Even Married Folks Can Give Off Neckbeard-Vibes
Image credits: ntlane2004