征服【せいふく】
conquest, subjugation, overcoming (a difficulty), conquering (e.g. a mountain), mastery (of a skill)
遠征【えんせい】
expedition, (military) campaign, tour (by a sports team, performer, etc.), visit
出征【しゅっせい】
going to war, departure for the front, departure for military service (in response to a draft)
長征【ちょうせい】
lengthy military expedition, Long March (China, 1934-1936), Long March (series of Chinese launch vehicles)