Spontaneous

прилагательное 1) самопроизвольный (происходящий без какого-либо внешнего воздействия) Синоним(ы): self-acting 2) добровольный Например: He made a spontaneous offer of help. — Он от чистого сердца предложил свою помощь. Синоним(ы): voluntary, freewill Антоним(ы): forced 3) непосредственный, непринуждённый; стихийный; неподготовленный, спонтанный Например: Nothing he says is spontaneous - he always thinks before he speaks. — Среди его высказываний нет ни одного необдуманного, он всегда подумает, прежде чем сказать что-либо. Синоним(ы): impromptu, unpremeditated, unrehearsed, natural, unplanned, extemporaneous 4) [ботаника] дикорастущий, дикий Например: spontaneous vegetation — дикая растительность

Большой англо-русский словарь

Spontaneous

adjective Etymology: Late Latin spontaneus, from Latin sponte of one's free will, voluntarily 1. proceeding from natural feeling or native tendency without external constraint 2. arising from a momentary impulse 3. controlled and directed internally; self-acting Example: spontaneous movement characteristic of living things 4. produced without being planted or without human labor; indigenous 5. developing or occurring without apparent external influence, force, cause, or treatment 6. not apparently contrived or manipulated; naturalspontaneously adverbspontaneousness noun Synonyms: spontaneous, impulsive, instinctive, automatic, mechanical mean acting or activated without deliberation. spontaneous implies lack of prompting and connotes naturalness Example: a spontaneous burst of applause. impulsive implies acting under stress of emotion or spirit of the moment Example: impulsive acts of violence. instinctive stresses action involving neither judgment nor will Example: blinking is an instinctive reaction. automatic implies action engaging neither the mind nor the emotions and connotes a predictable response Example: his denial was automatic. mechanical stresses the lifeless, often perfunctory character of the response Example: a mechanical teaching method.

Merriam-Webster's Collegiate Dictionary