The word "pre-cursor" refers to something that comes before or functions as a warning of something else to come. There are various synonyms that can be used to convey a similar meaning, such as "harbinger", "forerunner", "precursor", "herald", "prologue", "portent", "sign", "omen", and "augury". Each of these synonyms carry connotations of anticipation or warning, and can be used interchangeably in different contexts to create a nuanced effect. Whether referring to historical events, scientific phenomena, or artistic movements, the use of synonyms for "pre-cursor" can add depth, complexity, and richness to language.