Every ifMUD object can have one or more flags set.
You can use the @set command to set or clear a flag
(prefix the flag's name with a ! to turn off the flag):

@set me = male
@set me = !dark

     abode       dark        examinable  spy
     male        slippery    quiet       builder
     female      puzzle      book        noholler
     linkok      zoned       wizard      chownok
     jumpok      visible     expert      going
     noexclaim   nohilite    nochannel  

If you want help on a particular flag, type "help flagname". 
For example, "help dark" or "help expert".