What does this emoji mean? Is this a British thumbs up?

shaka when the walls fell

Its the Shaka, Hawaii’s official state hand gesture.

https://en.m.wikipedia.org/wiki/Shaka_sign

Of course the fucking Mormons are trying to own it.
- Who copied it from the freemasons
Thank you.
- This is way more accurate than that urban dictionary.
  
  In Hawaii (depending on where you are) shaka is used all the time. Kinda like waving to someone with a hint of good vibe to it. Also to emphasize "hey that's cool". You see it a lot waving thanks to cars, too
It is not the shaka. It's the "call me hand" emoji.
- It's not the call me hand, it's the hang loose emoji!

Dude, radical emoji. That's just a gnarly way of tell someone to hang loose, bro. I've usually seen it done left-to-right instead of up-and-down, but the universe is infinite so if you wanna flip it that's totally copacetic.

Edit: I started thinking about surfers and it dragged up memories of this legend on Tosh.0

It's good to hang loose? What if stuff falls out?
- "Hang loose" is what you tell someone who needs to chill out and let the waves carry them away from their problems man. Align your chakras with the Earth and so on.
  
  Seriously though, the reason I wrote like that is I'm using the slang of roughly 90s/2000s-ish California surfer culture, which is where the hand signal was used to tell people to relax and be happy. Or say hi and let them know you are relaxed and happy. If you imagine it as a gang sign for surfer hippies you aren't far off.
- Stop pooping at parties
- I'm starting to think you're not here in good faith.
Didn't like tosh.o much, but this one is pretty great

Directly translated it means "radical broh! let's smoke some weed."

Shaka brah

What's that mean?
- Check the urban dictionary link that Kokolores posted, that's your answer! :D
- Hang ten.
- Google.com

It may be Shaka, but in Unicode and emoji it's "call me" https://emojipedia.org/call-me-hand

The angle of the fingers is all weird. The middle three and the wrist should be pointing up-right, not up.
- The one on the GP's link is a bit better. Maybe even recognizable.
  
  I wonder what system the OP's one comes from.

https://www.urbandictionary.com/define.php?term=Hang+loose

Thank you.

The amount of people that dont know about shakas is killing me. No culture

I knew it meant "hang loose", but I've never heard the term.
- Known it as hang loose since the 80’s from Hawaii
- Dont need to have heard the term. Just need to know it's rough meaning. Some people really think it means "call me" which while a valid interpretation also messes with its actual meaning
Aging yourself, mate
Why ? The sign has different meaning in different cultures. It is just your ignorance of anything outside your bubble.

Isn't it a surfer thing? Like hang ten, radical, man.

https://wikipedia.org/wiki/Shaka_sign

When the walls fell!

It’s a friendly gesture. Shaka / hang loose.

This emoji has two meanings:

the "original" meaning is based on the "shaka sign" from Hawai'ian culture. It's often paired with the phrase "hang loose", which generally just means to relax, have a good time, etc.
When ~~mobile~~ telephones first started to become mainstream, they would have ~~an antenna that extended up and out of the phone chassis~~ a speaker and a receiver that you would speak directly into, so people picked up this gesture that mimicked the shape of a ~~cell~~ phone. Pressing it against your cheek with the pinky finger in front of your mouth and the thumb covering the opening of your ear would be accompanied by saying or mouthing "call me" was pretty universally understood and was one way to communicate the desire to speak on the phone from a distance where you could still visually see someone but shouting was ineffective or impractical.

edit: some people have clarified that the gesture predates cell phones, which makes sense.

This way predates cell phones. Handsets have been in use for... Nearly 100 years I think. Not sure exactly when the gesture caught on our it's origin.
I remember using the second definition in elementary school in the early 90s, before cell phones were on common use, long before they flipped open, and even before they had extendable antennas. I suppose they might have been a cordless landline, but I always assumed it was a corded phone. The "call me" message, then, wasn't about being able to see someone but not hear them except in very specific circumstances; instead, it was implied to mean "call me later." It could be used as a way of flirting, or it could be more platonic. I suppose it could also be used in a business setting, though I wasn't really old enough to know.

Symbol for the hand used like a good old telephone receiver. Thumb is near ones ear, the little finger is near ones mouth. Used here in Germany when land line were used more often to show someone behind a window: I'll call you (later).

Call me

I don't know you.
- When in doubt, see the emojipedia. Yes, there’s an encyclopedia for explaining what different emoji mean.
- Oh, that's just Blondie.
- 🤙

Hang ten. Or Call me? That’s a stretch but kinda like a phone

"Call me" is definitely what it used to mean in the 90s
- Only if you hold your hand to your head. This is hang ten, and you wiggle your wrist back and forth while looking totally radical, dude!

Some cultures have a way of counting to ten on one hand. This represents six in one version of that system.

1F919 - Call Me Hand

https://www.unicode.org/charts/PDF/Unicode-9.0/U90-1F900.pdf

Hang ten, dude!

Sometimes a pinky is fun

Ask genx

It's the "call me hand" emoji.

Hang loose, brah.

I think maybe this sub is a little too lenient with its name.

Would you rather lick she-hulk's pussy? Or get tied up with wonder womans truth lasso?
- She-hulk, final answer.
There were in fact stupid questions.

I'm surprised they made an emoji for something as obscene as this but you know that "two in the pink, one in the stink" thing for the shocker? This is along the same lines: One in the pink, one giving your lady a thumbs up to tell her you're a chill dude and having a good time.

Doesn't work as well on guys unless he's flexible or has a bunch of strategically-placed mirrors.