1) Ally 2) Assistant 3) Associate 4) Auxiliary 5) Cohort 6) Compatriot 7) Compeer 8) Confrere 9) Coworker 10) Friend 11) Mate 12) Workfellow 1) An associate 2) Associate 3) Co-worker 4) Collaborator 5) Fellow worker 6) French word used in English 7) Professional associate 8) Workfellow 9) Workmate 
• (v.t & i.) To unite or associate with another or with others. • (n.) A partner or associate in some civil or ecclesiastical office or employment. It is never used of partners in trade or manufactures.
[Noun] A person you work with.
Col'league (kŏl'lēg) noun [ French collègue , Latin collega one chosen at the same time with another, a partner in office; col- + legare to send or choose as deputy. See Legate .] A partner or associate in some civil or ecclesiastical office or employme...Col·league' (kŏl*lēg') transitive verb & i. To unite or associate with another or with others. [ R.] Shak. 
[n] - an associate you work with 2. [n] - a person who is member of your class or profession
noun a person who is member of your class or profession; `the surgeon consulted his colleagues`; `he sent e-mail to his fellow hackers`co-worker noun an associate you work with
an associate.