Do you use the word "firm" with "friends"? I thought "firm" is used with the objects.
No, it is not typical to use the word "firm" in this way to describe friends as it is normally an adjective used for objects. However in some cases, "firm" can express the meaning of "strong", "enduring", or "constant", and so it can be used to refer to a long-lasting relationship or friendship between people. This is more common in British English and sounds a little formal when used this way. Ex: Our relationship is firm. Ex: We are firm believers in education.