spontaneous
adjective
[ spɒnˈteɪnɪəs ]
• performed or occurring as a result of a sudden impulse or inclination and without premeditation or external stimulus.
• "the audience broke into spontaneous applause"
Similar:
unforced,
voluntary,
unconstrained,
unprompted,
unbidden,
unsolicited,
unplanned,
unpremeditated,
unrehearsed,
impulsive,
impetuous,
unstudied,
impromptu,
spur-of-the-moment,
extempore,
extemporaneous,
unschooled,
untaught,
uninstructed,
off-the-cuff,
Origin:
mid 17th century: from late Latin spontaneus (from ( sua) sponte ‘of (one's) own accord’) + -ous.
