背中合わせ せなかあわせ Meanings Noun back-to-back; facing in opposite directions two sides of the same coin; inextricably linked (esp. with something dangerous or undesirable) on bad terms; at odds Kanji 背 back. Read as せ. 中 middle. Read as なか. 合 fit. Read as あわせる. Jinuma: Japanese Dictionary · Word lists