"noun | ein·juhl in·vest·er
A rich, ballsy mofo who throws cash at startup pipe dreams in hopes of getting in on the ground floor of the next Facebook. Angel investors are the sugar daddies of Silicon Valley, sprinkling their seed money on thirsty entrepreneurs with big ideas and empty pockets. But hey, high risk, high reward, right?"
Example
"I need an angel investor to fund my app that's like Uber, but for pet rocks."
"My wife's boyfriend is an angel investor, so I'm hitting him up for some funding for my meme-based cryptocurrency."
"I heard Ashton Kutcher is an angel investor now. Dude, where's my Series A funding?"