workfellow, confrere, fellow, co-worker, fellow worker, collegue, associate, adjunct, ally, collegiate, more...

competitor, adversary, opponent, rival, antagonist

former, older, senior, younger, dear, close, male, junior, french, american, professional

group member,   member of a group,   work partner,   work friend,   business associate,   member of group,   peer of sorts,   a member of a group,   work mate,   work buddy