A High-Level programming language is a language that encourages to programmer to avoid low memory control structures and work on higher levels of abstractions.
Hence, many such languages automate many processes such as memory allocation and freeing as well as implementing many protocols for the programmer to use (Batteries included language).
This contrasts with low-level programming languages which explicitly provide and encourage taking control of low level primitives.
The term "high-level" is relative and thus, the meaning of "high-level programming language" is also always changing.
The accepted lower end for high-level languages in the public discourse are currently languages like Java or Pascal.
Taking them as the baseline, the term currently includes languages like...
Game development in such languages is possible, but discouraged for bigger projects.
Lets take Python and C as examples.
Both have game libraries and game engines available and both can be used to make games from scratch.
For simple games, you will not notice a difference, given, that you are proficient in both languages.
But depending on the benchmark, Python is on average 100x slower that C.
That can be the difference between rendering in 1000 ms (1 FPS) or 10 ms (100 FPS).
Since games are often very performance critical applications, high-level languages often rely on libraries to compute efficiently.
Those libraries are often written inside low level languages and are thus more performant.
But calling code from another language has performance panelties.
In well written and performance optimized python code, you will spend most of your time, translating data between library functions and Python itself.
You will also be hampered in your ability to write your own functions, since the moment you loop in Python, all performance is lost.
In the beginning of a game project you hence must make the decision, if you will need the performance down the line and which part of your game will be performance critical.
You can read more about that in this article.