I saw a blue Zegna blazer that was exactly like a suit jacket. That was in a legit retail store. I told the salesman, this is like a suit jacket. He disagreed, but couldn't tell me what the difference was...
So I guess it's possible that this really a "blazer". On the other hand, if it looks like an orphaned suit jacket, that's what the onlooker will think it is, regardless of whether you bought it as a blazer or not.