In reference to the saying "off the chain.", Chainless is above and beyond even ever having a chain to be broken away from. To refer to something as being "Chainless" you are making someone, or thing to be close, or to be the best; in terms of fun, exciting, outlandish, or crazy. All of which are in a good way.
1. Yo Sean's party last night was chainless.
2. Did you see that outfit she was wearing? That shit was chainless.
3. Sean is just straight chainless.