Be good friends - Idioms by The Free Dictionary
be good friends
be (just) good friends
A phrase used to emphasize that two people are not in a romantic relationship. Oh, he's not my boyfriend—we're just good friends.
be (just) good ˈfriends used to say that two friends are not having a romantic relationship with each other: People often think Ian and I are a couple, but we’re just good friends.
References in periodicals archive
Ahmed Ali Butt: "Yes and you can be good friends
with your ex."
She says it's stupid to have a boyfriend while I am a young teenager and that it's better to just be good friends
with a guy.