 You can't buy a best friend like that. But you can adopt one. There are millions of pets waiting for a best friend just like you. Help us save them all at bestfriends.org. AdoptUSKids presents What to Expect When You're Expecting. A teenager learning the lingo. Jelly. Jelly adjective. Jelly is a shorter, better way to say jealous. As in, Chloe, I am like so jelly of your unicorn phone case.