spontaneous
/spɒnˈteɪnɪəs
/adjective
1Performed or occurring as a result of a sudden impulse or inclination and without premeditation or external stimulus: the audience broke into spontaneous applause a spontaneous display of affection...
- She's so lively and smiley that her responses to the audience seem entirely unforced and spontaneous.
- The audience alternated compulsive chatter with breathless silence, and there were three or four mid-film bouts of spontaneous, delighted applause.
- For the second time in the festival, the crowd broke into spontaneous cheers and applause as the village women stood up against the oppressive regime of their village.
Synonyms
unforced, voluntary, unconstrained, unprompted, unbidden, unsolicited, unplanned, unpremeditated, unrehearsed, impulsive, impetuous, unstudied, impromptu, spur-of-the-moment, extempore, extemporaneous;
unschooled, untaught, uninstructed
informal off-the-cuff
1.1Having an open, natural, and uninhibited manner.Both improvisation and the musical hold the contradictory idea that spontaneous performance is available to all and that some people are more spontaneous or open than others....
- Everything from Finny's appearance to his walk to his personality is natural and spontaneous.
- Whistler's charm was genuine and completely spontaneous.
Synonyms
natural, uninhibited, relaxed, unselfconscious, unaffected, easy, free and easy;
impulsive, impetuous;
open, genuine
1.2(Of a process or event) occurring without apparent external cause: spontaneous miscarriages...
- Some spontaneous abortions, apparently, ‘can be seen as a woman's reproductive organs unconsciously deciding not to go ahead with this pregnancy’.
- The spontaneous form of Creutzfeldt-Jakob disease, the one not linked to consumption of beef or anything else, claimed over 1,000 Brits in the same time period.
- I guess it's something like spontaneous human combustion, only different.
1.3 Biology (Of movement or activity in an organism) instinctive or involuntary: the spontaneous mechanical activity of circular smooth muscle...
- For what it's worth, a zooid is ‘an organic cell capable of spontaneous movement independent of the parent organism.’
Synonyms
reflex, automatic, knee-jerk, involuntary, unthinking, unconscious, instinctive, instinctual
informal gut
1.4 archaic (Of a plant) growing naturally and without being tended or cultivated.
Derivatives
spontaneousness
Origin
Mid 17th century: from late Latin spontaneus (from (sua) sponte 'of (one's) own accord') + -ous.