1. be welcoming to new ideas/suggestions/concepts
have an open mind about it, be open-minded
To use this as a noun, you can say that someone is 'open-minded'. Having an open mind means that you are interested in new ideas and you are happy to have your thoughts and beliefs questioned and challenged. It is almost as if your brain is open to allow more information in. The opposite of this is to be closed-minded or to 'have a closed mind'.