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spon·ta·ne·ous

(spŏn-tānē-əs)

adj.

1. Happening or arising without apparent external cause; self-generated: a microorganism capable of spontaneous movement.

2. Arising from a natural inclination or impulse and not from forethought or prompting: spontaneous laughter; a spontaneous protest.

3. Unconstrained and unstudied in manner or behavior: a spontaneous personality.

4. Growing without cultivation or human labor: spontaneous vegetation.

[From Late Latin spontāneus, of one's own accord, from Latin sponte; see (s)pen- in the Appendix of Indo-European roots.]

spon·tane·ous·ly adv.

spon·tane·ous·ness n.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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