Adjective spontaneous has 3 senses
- spontaneous, self-generated - happening or arising without apparent external cause; "spontaneous laughter"; "spontaneous combustion"; "a spontaneous abortion"
Antonyms:  induced, elicited, evoked, iatrogenic
 - ad-lib, spontaneous, unwritten - said or done without having been planned or written in advance; "he made a few ad-lib remarks"
Antonyms:  scripted, written (indirect, via unscripted)
 - wild, spontaneous - produced without being planted or without human labor; "wild strawberries"
Antonym:  planted (indirect, via unplanted)
 
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