It’s the vocabulary of utterly deranged sociopaths. Your life will not be improved by this knowledge.

• ROI: return on investment.
• “hodlers”: some cryptobro once mis-spelled “hold” as “hodl”. Because cryptobros can’t ever be wrong or make mistakes, it was retroactively turned into an acronym for “Hold On for Dear Life”. Outside the circus tent, people use it to mock them.
• “bearproof”: “bull market” and “bear market” are terms from stock trading for circumstances where the valuation of something rises or falls respectively (because a bull attacks upwards and a bear attacks downwards – again, sociopaths). Therefore, a “bearproof” investment promises to resist bear markets and only ever rise in value, inevitably followed by the value crashing to effectively zero.
• “To the Moon”: a common catchphrase, used by crypto scammers, to indicate that a shitcoin will have an extremely high value Soon^TM (spoiler alert: it never happens).
• “Diamond hands”: someone who holds onto their investments even if the market is unfavorable. The opposite is “paper hands”: someone who sells an investment as soon as the value falls even a little. Used by cryptobros to manipulate their audience.
• “Line go up”: infinite growth mentality. Stonks.
• NFT: oh boy.