Foiler, a noun that refers to someone or something that spoils, disrupts, or frustrates the efforts or plans of others, can be described with various synonyms. One such synonym is "thwart", which means to prevent someone from accomplishing their goals. Another term synonymous with foiler is "saboteur", which describes someone who deliberately undermines or damages a project, organization, or plan. Additionally, the word "hindrance" can be used to portray a foiler, emphasizing the obstruction or barrier they create. Other alternatives include "interferer", "obstructer" or "disruptor", which all capture the essence of one who hampers or obstructs progress. Thus, these synonyms effectively illuminate the concept of a foiler and enable diverse expressions while describing such individuals or actions.