Some states do use their own definitions of terrorism to explain why it’s bad when other people do it but OK when they do it, but that’s definitely not a uniform definition.

the calculated use of violence to create a general climate of fear in a population and thereby to bring about a particular political objective.

- Britannica

The use of violence or the threat of violence, especially against civilians, in the pursuit of political goals.

- American Heritage Dictionary of the English Language

the use of intentional violence and fear to achieve political or ideological aims. The term is used in this regard primarily to refer to intentional violence during peacetime or in the context of war against non-combatants.

- Wiki

(Government, Politics & Diplomacy) systematic use of violence and intimidation to achieve some goal

- Collins English Dictionary

the use of violence and threats to intimidate or coerce, esp. for political purposes… government or resistance to government by means of terror.

- Webster’s

While stuff like Tomb Raider is the quintessential example, for a five year old you would probably be better with something more colourful and fun, even if you are the one playing it.

With that in mind my first thought was A Hat in Time although I’ve not played it through to verify end to end appropriateness.

You could also try Mirror’s Edge because bright colours and dynamic movement, I don’t remember it being that violent but maybe on second thoughts consider the safety aspect of introducing a child to the concept of jumping between buildings and maybe I’m talking myself out of this.

Celeste is colourful and fun and honestly at that age I don’t know that she would pick up that much on the heavier aspects of the story which are allegories for anxiety/depression/gender dysphoria. A five year old is basically going to see it as a story with an evil twin I think.

I haven’t played Child of Light but that might be appropriate?

The main character in Crypt of the Necrodancer is a girl called Cadence, although that is one you would really have to enjoy to make it worth it imo. I’m mostly thinking rhythm and bright colours are child friendly again to be honest, but you still have to play what is basically a roguelike mixed with a rhythm game and if that’s not your jam it will be a waste of money.

You can always play a game with selectable skins too, like Spelunky 2 has a few characters you could pick between which all play the same but has a variety of designs you can play as.