From my perspective, the three distinguishing features of Clojure from other languages/Lisps in general are:
1. It's a lisp, which means homoiconic, i.e. build software just like Lego (different from non-lisps)
2. Immutability and purity in the core library + sane, managed concurrency via atoms, refs, core.async, i.e. write serious multithreaded code without putting your hair on fire; helps on the front-end via ClojureScript as well (different from most other Lisps)
3. The JVM, which means very good performance in the general case + build once, run everyone + a lot of libraries
1. It's a lisp, which means homoiconic, i.e. build software just like Lego (different from non-lisps)
2. Immutability and purity in the core library + sane, managed concurrency via atoms, refs, core.async, i.e. write serious multithreaded code without putting your hair on fire; helps on the front-end via ClojureScript as well (different from most other Lisps)
3. The JVM, which means very good performance in the general case + build once, run everyone + a lot of libraries