* Lord: This is a term of respect, often used for a ruler, especially in historical contexts.
* Leader: While not specific to royalty, it can be used to describe someone who holds a position of power and authority.
* Lieutenant: This refers to a deputy or second-in-command, often in a military context.
If you can give me more information about the specific situation where you need an alternative to "king," I might be able to suggest a more fitting word.