1. A difficult or demanding project, job, or assignment that requires significant effort, skill, or determination to complete
Learning a new language is a challenging undertaking.
Aprender um novo idioma é uma empreitada desafiadora.
2. An ambitious or formidable endeavor that presents obstacles or difficulties
Building a house from scratch proved to be a challenging task.
Construir uma casa do zero mostrou ser uma empreitada desafiadora.