&#x27;Expressive&#x27; means that it&#x27;s <i>easy to write code that&#x27;s easy to understand</i>.<p>JS doesn&#x27;t even come close to the expressiveness that you get in C# due to the fact that in JS, you don&#x27;t even know the type of arguments being passed in any given function without looking elsewhere in the code - therefore, it&#x27;s not easy to understand.<p>If you&#x27;re going to go with the definition that says expressiveness means &quot;the variety and quantity of ideas that can be expressed&quot;, Javascript also loses there since there are <i>whole classes</i> of behavior that cannot be practically expressed in Javascript. For instance - try writing a function that only accepts a standard single precision floating-point number as it&#x27;s  argument and see how much work you have to do compared to other languages.<p>Try expressing a Dictionary, Linked List, HashTable, SortedList, SortedDictionary, etc in JS - you&#x27;ll be writing those structures yourself or cobbling together some random lib. Better languages let you actually express those things without having to write them yourself.