LIQUIDITY

I've been using this word - "liquidity" - in my ballet class lately to describe the quality of movement I'm searching for.  I always used it as a joke because I was pretty sure it wasn't a word - or at least I thought I was probably using it in an incorrect context.  But if I may just use it this one last time... this video of a very short excerpt of Alonzo King's work is the very definition of "liquidity" that I've been after.  What would you call it?