extraordinarily large in size or extent or amount or power or degree, The word enormous contains within it, if you look closely, the root norm, as in normal. So what you’re saying when you call something enormous is that it’s beyond what is normal;
Embark means to begin (a course of action). When you embark on something, you are starting it — and it's exciting. You might embark on a new career or embark on a trip to the Galapagos Islands. You wouldn't embark on a trip to the grocery store.