Seriously means in a way that shows you're being earnest, thoughtful, or treating something as important.

When your teacher says “I'm seriously impressed with your work,” she means she genuinely admires what you've done, offering real praise. When a friend asks “Are you serious?” after you share surprising news, they're checking whether you're telling the truth or kidding around. If your parents tell you to take your homework seriously, they want you to focus and do your best work, giving it proper attention and effort.

The word can also mean to a great degree or extent. If someone is seriously tall, they're remarkably tall. If you're seriously considering joining the robotics club, you're thinking about it carefully, weighing the pros and cons.

Sometimes people use “Seriously?” as a one-word question to express disbelief or frustration, like when your sibling eats the last cookie you were saving: “Seriously?”

The opposite would be doing something carelessly, jokingly, or without real attention. Taking things seriously means recognizing when something matters and giving it the effort and respect it deserves.