He tried hard to suppress his tears, not wanting to break down in front of everyone.

suppress 由前缀 sup-（表示"向下"）和词根 press（按压）组成，字面意思是"向下压"。引申为"抑制、忍住（情绪或行为）"，在这里指努力控制住不让眼泪流出来。