Chum

Definition: (from dictionary.com)
-noun
1. a close or intimate companion
2. a roommate, as at college

Examples:

"A glass of milk is like an Oreo's best chum - you can't have one without the other!"

"I never thought a sponge and a starfish could be chums, but Spongebob and Patrick have proved me wrong!"

Origin: (from etymonline.com)

"'friend,' 1680s, university slang, alternative spelling of cham, short for chamber(mate), typical of the late-17c. fondness for clipped words. Among derived forms used 19c. were chumship; chummery 'shared bachelor quarters,' chummage 'system of quartering more than one to a room.'"

Awkwardness rating: 5

Although Spongebob and Patrick are chums, they spend very
little time at the Chum Bucket. (monstersandcritics.com)