On the left we see the abbreviated form of KNIFE, BLADE as the determinant (key). 刀 dao means knife. So we know this word has something to do with a sharp object, likely made of metal. Here, dao represents the master’s sword.
On the right we see a strip of cloth 巾 （fabric is represented with jiong 冂 which is a covering symbol for covering; support of the fabric is with gun a vertical line 丨）。
A master is a person with a sword and scabbard. Who has A SWORD and a SCABBARD? The Master.