Yes, I get your point, but I also have other blondes in the story - a platinum blonde and just, well, a blonde-blonde. I understand what you are saying, but I did grow up with a cousin whose hair was 'dirty blonde', and everyone called her hair color that. But like I said, I need to specify, since I do use hair color as an indicator of which character I'm refering to in my story. Since, like I mentioned first, there's more than one blonde, I chose to do it this way. Thanks for explaining ..
of course the hair color is commonly called that... but what we're getting at is that the person isn't.... except by you, in your story... so it might be confusing to readers, who think you're saying the 'blonde' woman is dirty, unless you're also referring to other characters not by name and only by 'the strawberry blonde' and 'the blonde-blonde' which we couldn't have been aware of till you told us...