Ranking friends.

Acquaintance

Too dull; just "some guy,"  really

Adjunct
Professional connection, so you're stuck together

Clubber
Okay if you're in the Drones with Bertie Wooster; otherwise barely above Adjunct

Well-wisher
Friendly person who doesn't really do anything for you

Connection
Does something for you but is not friendly

Abettor
Does something with you that is not friendly

Associate
Does something with you, but there's no warmth

Colleague
An Associate with warmth

Peer
Someone you're really eye-to-eye with, except maybe in England

Fellow
A guy you know and like who is on your level; now we're getting somewhere

Ally
A Fellow that you can count on

Compatriot
A closer Ally; less likely to stab you in the back

Collaborator
Even less likely to stab you in the back, lest you both go to the big house

Confederate
Unity of vision leads to greater loyalty

Companion
Someone you can endure traveling with

Crony
Someone you can endure swiping money with

Accomplice
Someone you could endure going to jail with

Teammate
Pulling the oars for the same boat, but he could suck at it

Partner
Pulling oars in the same two-man boat, so he'd better not suck at it (TV cops would rank this higher)

Cohort
People see you together, they know you're up to something

Comrade
People see you together, they think "Molatov cocktails"

Pal
Someone you actually like

Mate
Someone you like even more, at least in Australia

Homeboy
Guy from the 'hood upon whom your favor rests

Crew
Guy from the 'hood whom you trust

Pard
Guy from the ranch whom you trust

Confidante
Guy you really trust but may not like so much

Brother from another mother
A good guy, but one who seems a little phony

Wingman
Guy you can't do with out, until a girl comes between you; think the "Road to" movies

Chum
A good guy, period

Amigo
A good, fun guy

Stalwart
Someone who would go to jail for you

Buddy
Someone you would go to jail for

Blood brother
Someone you have bled for

Friend
Top of the heap; someone you would bleed out for

Not on list:

Supporter (too subservient); Disciple (too subservient; too biblical); Helper (too subservient; too blah), Entourage (too subservient; too showbiz---and there's no actual friends in showbiz).