guard, war=見守る
reward / 後ろを見守る→報いる、報酬
cf. I had no reward for all the hard work I did.
regard / 後ろを見守る→振り返って見る→考える、評価する
cf. She regards her job as the most important thing in her life.
warden / 見守る人→監視人
cf. The prison guards don't like their boss, the warden.