A male friend; a man who is a friend (not a romantic partner).
大学には男友達がたくさんできた。
I made a lot of male friends at university.
彼女は男友達と二人きりで食事に行くのを嫌がった。
His girlfriend disliked him going to dinner alone with a male friend.
ただの男友達だと言っていたが、関係は少しぎこちなかった。
He said they were just male friends, but the relationship was a bit awkward.
旅行には男友達を何人か誘った。
I invited several male friends on the trip.