1. They decided to call the baby Mark.
2. They decided to name the baby Mark.
(Are both the same?)
3. Lee was standing right behind her.
4. Lee was standing just behind her.
(Are both the same?)
5. They hired a private detective to find their missing child.
6. They hired a private detective to find their astray child.
(Are both the same?)
7. My vision is blurry these days.
8. My vision is clear these days.
(Is 'blurry' the opposite of 'clear'?)
1 and 2 mean the same, yes.
3 and 4 mean the same.
5 is correct, but 6 is not. The word "astray" is an adverb and is usually used in phrasing like this ~~> They were looking for their child who had gone astray.
Yes, "blurry" and "clear" are opposites.