A book or any other piece of writing is unread if you have not read it. Once you have read a book, and then give it to someone else who hasn't read it, it becomes unread again to the new person.
Something is unsafe if it has a high risk of danger. The man in the picture has chosen an unsafe way to reach the roof he is working on. Unsafe is the opposite of safe.
Something is untucked if the loose edge of something is flapping and is not held in place. The man in the picture has his shirt untucked. Untucked is the opposite of tucked.
Something is unusual if it is not what you expect for something of that kind. Something unusual is not ordinary.
The person in the picture is wearing an unusual hat.
Up is a direction. You go up when you go higher. The person in the picture has just climbed up the ladder and is now sitting at the top. The opposite of up is down.
