“Travail” refers to a painful or laborious effort, so it follows that the adjective form, “travailous,” would describe something that causes or involves intense effort. There is one notable difference between the parts of speech: A second definition of the noun “travail” is “labor pains” (as in giving birth), and the definition of the adjective “travailous” is not specifically linked to that process. However, talk to people who have been through travails, and you will likely hear stories of their travailous experiences.