classmate (n.)

• ace
• amigo
• associate
• bedfellow
• buddy
• bunkmate
• butty
• chum
• colleague
• companion
• company
• compeer
• comrade
• confrere
• consort
• copartner
• crony
• fellow
• gossip
• infant
• kindergartner
• mate
• messmate
• pal
• pard
• pardner
• partner
• playfellow
• playmate
• preschooler
• roommate
• schoolboy
• schoolfellow
• schoolgirl
• schoolmate
• shipmate
• sidekick
• tablemate
• teammate
• workfellow