set keywords

SET KEYWORDS [words]  -  define CCMD completions for KEYWORD command

The KEYWORDS variable defines one or more words to be used to complete
  a KEYWORD command with CCMD.  Command completion is the CCMD feature 
  that lets you use the TAB key to fill in the rest of a partially typed 
  word or command.

To unset it, type SET KEYWORDS with nothing following.

Example:
    MM>set keywords doughnuts
  Then you can type:
    Send>keyword do[TAB]
  and CCMD will find "doughnuts" in your KEYWORDS variable and fill in:
    Send>keyword doughnuts

For more help, type "help" and one of the following:
(at any prompt:)  save-init   set   show   keyword   ccmd