comrade or chum (often used as a term of address).

bud 2 .

to be a companion; be friendly or on intimate terms. ?

buddy up,

to become friendly; be on friendly or intimate terms.

to work closely together

to buddy up with a student from another high school.

buddy up to, to become friendly with or curry the favor of

He was buddying up to the political bosses.

noun

enemy

noun

associate , chum , co-mate , companion , comrade , confidant , co-worker , crony , intimate , mate , pal , peer , sidekick , amigo , brother , confidante , familiar , fellow , friend , pard