What is considered "Homophobic"

What is considered "Homophobic", because, like I'm religious, but I personally would never shame a person from the LGBTQA+ community, but there is a problem with how people describe; "Homophobic people". My classmate is always like, "You either supportive, or homophobic." But they fail to acknowledge some of use are religious, and would like to everything our religion says.
So can a person be accepting and not supportive in a sense that they them-self would not practise LGBTQA+ activities, but they have no problem if their friend/co-worker were to do so?