uninvited (adj.)

• arbitrary
• autonomous
• discretional
• discretionary
• elective
• free
• gratuitous
• independent
• nonmandatory
• optional
• self-acting
• spontaneous
• unacceptable
• unasked
• unasked-for
• uncalled-for
• uncoerced
• undesirable
• undesired
• unforced
• uninfluenced
• unprompted
• unrequested
• unsolicited
• unsought
• unwanted
• unwelcome
• unwished
• voluntary
• volunteer
• willful