Serious Answer:

It doesn't "stand for" anything in that it's not an acronym or acrostic.

It's the name of Star Trek "tropical resort planet." People go on shore leave there in the way that people go on vacation to Bermuda or the Bahamas; it's kind of the default "iconic tropical paradise" location.

On one notable occasion, Captain Picard went on vacation there.

Before he left, Commander Riker asked him to pick him up a certain souvenir from there.

You see the wooden statue in the sidebar over there? --->

That thing. It has a name. I don't remember what it's called.

What Riker didn't tell him is that displaying one of those statues openly is basically Risan shorthand for "I'm cruising for casual sex." So Picard was just like "yeah, I finally got around to buying Will that ugly statue he wanted; can't be arsed to take it back to my room right now though." So he just kinda carried it around with him for the day, had it hanging out on the table next to him while he was reading and such. With predictably awkward/hilarious results.

So yeah. This community is named after a low-stress tropical tourist trap that was occasionally spiced up with adventure and trolling. The perfect place for Star Trek related memes and shitposts.

It's an acronym for the Romulan Imperial Spacefaring Academy.

You want jamaharon you dirty boy

Serious Answer:

It doesn't "stand for" anything in that it's not an acronym or acrostic.

It's the name of Star Trek's "work prison." People can't exactly be fired or ejected from starfleet; it's kind of like a PIP, but instead making it mildly unpleasant until you get bored and leave of your own accord.

On one notable occasion, Captain Janeway was sent there.

Before she left, Commander Chakotay asked her to check in on a friend of his who had been there for years.

You see the wooden statue in the sidebar over there? --->

That thing. It has a name. I don't remember what it's called.

What Chakotay didn't tell her is that his friend was literally a block of wood. In fact, that's why he was at Risa. So Janeway was just like "yeah, I really don't understand what's happening but after asking for an introduction to this dude I have been sent to this little statue like 6 times. I guess there's something to it." So she just kinda carried it around with her for the day, had it hanging out on the table next to her while she was reading and eating and, well, changing clothes. With predictably awkward/hilarious results.

So yeah. This community is named after Star Trek's hilarious take on how to deal with subpar job performance. In the end, Risa was actually a pretty chill place. The perfect place for low effort Star Trek related memes and shitposts.

Serious answer:

Risa deez nutz

Serious Answer:

It doesn't "stand for" anything in that it's not an acronym or acrostic.

It's the name of Colonel Mustang's bodyguard.

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Remember that one episode where they say: "Risa Jar Jar Binks!".
Yeah, it's that.

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It takes about 5 minutes after arriving to find an alien willing to hump you dry.