When you hear "Engineer", you often think of calculus, statistics, formal testing, requirements gathering, documentation, repeatable results, etc... along with a fundamental understanding of the problem space and possible solutions.

I think this is akin to NASA working on the Apollo program vs. someone in their garage attempting to build a go-cart for the first time.

When you just slap things together and see if they work - are you really engineering? Can you exactly repeat the process and achieve exactly the same result every time?

I think we often cross "research and development" with "engineering". Exploring a problem space and tinkering with concepts isn't engineering. Taking what you've learned, planning out and executing a solution to a precise set of requirements, and being able to repeat your steps and achieve those results again and again - is engineering.