Which of the following words is commonly used to indicate a contrast?

The word "however" is commonly used to indicate a contrast, making it the correct choice. In writing, "however" serves as a transition that signals a shift in thought or introduces an opposing viewpoint or idea. For example, if a text presents an argument or a situation, following it with "however" indicates that the subsequent statement will contrast with or provide an exception to what has previously been mentioned.

In contrast to "however," the other words have different functions. "Moreover" is used to add information, reinforcing an idea rather than contrasting it. "Consequently" indicates a cause-and-effect relationship rather than a contrast, showing how one idea leads to a result. "Likewise" suggests similarity between two ideas or examples, which also does not indicate a contrast. Therefore, "however" effectively communicates a change or contradiction in the discussion.