Rant Mode: Engaged.
The word “expressive” is often bandied about when describing the features of a language. In the same way that every new CSS framework that hits the front page of Hacker News is “light-weight”, “modular”, and “modern”, everyone’s favourite language will be at some point described by them as expressive.
Whether or not a language is expressive is a relative measure. To be expressive is to effectively convey thought or feeling. There are some languages that are so expressive that you immediately understand the author’s intent without needing to know the syntax. Take the following lines of Ruby, for example: