What is an antonym for "difficult"?

An antonym is a word that has the opposite meaning of another word. In this case, the word "difficult" implies something that requires a lot of effort, skill, or work to accomplish. The word "easy" directly contrasts with "difficult," indicating that a task can be done with little effort or is more straightforward.

The other choices, while they may describe various aspects of difficulty or effort, do not serve as direct opposites to "difficult." "Challenging" can imply a significant level of difficulty; "complex" suggests something that may be intricate or complicated, which does not necessarily mean it is easy; and "strenuous" relates to requiring great effort, which is again contrary to the idea of something being easy. Therefore, "easy" is the clear opposite of "difficult."