What does "mutator" mean?

That which causes mutation or change.

What is a synonym for "mutator"?

Common synonyms include: setter, setter.

//ˈmjuteɪtɚ// noun

noun ·Rare ·Advanced level

Noun

1
That which causes mutation or change.
"In object-oriented programming, the mutator function changes the value of the field that gives its name."
2
A setting which alters specific gameplay mechanics, such as rules, physics, or abilities.
"Rocket League will gain match-modifying mutators […] The football-meets-cars mashup will let you toggle on gameplay-changing settings such as low gravity, time warping and explosions."