1. A king.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• realx,
• ree,
• forex,
• rexi,
• mex,
• aex,
• req,
• nex,
• rey,
• erea,
• nexw,
• lurex,
• rec,
• trex,
• regu,
• rext,
• relux,
• lexy,
• rez,
• chx

• resh,
• recco,
• reach,
• Reece,
• res,
• reaux,
• Reese,
• Reiko,
• Reza,
• recce,
• Reis,
• Rees,
• Rewis,
• resew,
• reys,
• rega,
• Reyes,
• RESS,
• reiss,
• reich,
• Reck,
• recio,
• Resch,
• reek,
• reuss,
• reccy,
• reuse,
• ReGo.

The adjective form of the word "Rex" is "regal".