Bestie
лучший друг/ подруга.
Пример:
It was fun hanging out with my bestie.
Befriend (глагол)
стать чьим-то другом, особенно другом того, кому нужна ваша помощь. Очень близко по значению с "взять под опеку".
Пример:
I was befriended by an older girl at school.
Affinity (for/with somebody/something, between A and B)
чувство глубокого понимания и симпатии к кому-либо/чему-либо. Чувство родства.
Пример:
He had a deep affinity with his mother.
Sam was born in the country and had a deep affinity with nature.
Main man
важный и надёжный друг.
Пример:
Of course I trust you - you are my main man!
Meetup
неформальная встреча.
Пример:
You are welcome to attend the meetup on Sunday.
Plus-one
тот, кого берут с собой на какое-либо мероприятие.
Пример:
Before you bring a plus-one to a wedding, make sure you were actually invited with a guest.
Crony
человек, с которым кто-то проводит много времени (данное слово носит неодобрительный характер).
Пример:
He was playing cards with his cronies.