unprompted
1. [ adjective ] proceeding from natural feeling or impulse without external stimulus
Synonyms: impulsive
Examples:

"an impulsive gesture of affection"

Related terms: spontaneous
Similar spelling:   unpromised
  unproved
  unframed
  unprotected
  unprovoked
  unfrosted
  unfretted
  unprocessed
  unappreciated
  unprofitable
  unpredicted