Crossdressing, like so many other terms used under the transgender umbrella, is just a label, and the problem with labels, is that overall, they don't do a very good job of describing individuals. That said, I have always thought of crossdressing as the simple act of wearing clothing generally made and marketed to the opposite gender. Back when I thought I was a crossdresser and attached myself to that label, I began to realize that for me, it was so much more than the clothes. I just wasn't satisfied wearing the garments, I wanted to look feminine, feel feminine, and when I am en femme, I act feminine as well. So, it's way more than just the clothes, yet I also accept the fact that I don't want to transition or be full-time.
Hugs,
Sally