mutual 着重彼此共有或共享，局限于双方的关系。
common 侧重两人或多人共有共同，但不暗示彼此间存在的等价关系。
joint 强调至少两人或两方共同占用，侧重指一个统一体。
reciprocal 着重互惠，有来有往。
参考例句
1. It should be a mutual relationship. 应该是一个互相的关系。
2. That of course need mutual efforts. 这当然需要共同的努力。
3. It is the mutual duty of all to practice Christian forbearance, love, and charity towards each other. (Patrick Henry). 彼此施行基督徒的忍耐、爱和慈善是所有人相互的责任。（帕特里克·亨利）。
英英解释
adj.
1. common to or shared by two or more parties
2. concerning each of two or more persons or things; especially given or done in return
