bosom friend literary
bosom buddy literary
bosom pal literary

The first was affection of the kind that binds families together, or bosom pals.

Half-a-dozen shots in all, and it would seem they were bosom pals.

Then even the stable-boys, who were usually his bosom pals,would despise him as a ninny.

He had a bosom pal called George Neumiller with whom he often played duets.

"You don't really expect us to be bosom pals, do you?"

Obviously she thought it would be nice if we'd be bosom pals, or at least pretend to be, in a civilized manner.

It is an open secret that he and Reg Pybus are bosom pals.

We're going to be friends, Ogar, real bosom pals.

Benny and Garry were bosom pals once again.

"We ain't what you'd call bosom pals."