Usage examples (4)

• Adjective : A reply is desirable but not obligatory. ,duties obligatory on all. ,an obligatory promise
• Use the other part of the pie to indicate how much of your circle is nonobligatory.
• I was the first to arrive for the nonobligatory lunch, and it was only reluctantly that he led me to the assigned table.
• Of course, the friends would also prefer that even the nonobligatory suggestions be mostly good ones, so they won't have to spend too much time going through and...