break off [【形式ばった表現】 renounce] one's friendship 《with》
break 《with》
have nothing more to do 《with》 (絶交する).
友達がいに
for friendship's sake
person defined by personal relation (person who is a friend such as school friend, fishing buddy, classmate, etc.)
友達になる
a true friendship with one's best friend
They are intimate friends.
a relationship of being best friends with somebody
友達と一緒にいる
よい友だち