The word spontaneous It is widely used in our language to express what is done voluntarily, that is, it was not urged by force, by outside agents, or by an order, to be carried out. It is directly produced and arises naturally. The help of the people was spontaneous given the magnitude of the catastrophe, practically the authorities did not have to summon assistance.
To the word then we can apply it in relation to facts, events, which just stand out for occurring in a hyper natural way, or failing that, it can be applied in relation to individuals to account for that this or that acted naturally and moved by sincerity, that is, did not mediate an order.
It should be noted that the spontaneous individual will be defined in this way by executing actions or behaviors that are closer to the unreasonable one. Basically, these people are moved, driven by their instincts, their emotions, as opposed to just reason. The spontaneous person does not think too much about what he says, but if something comes to his mind, he expresses it without thinking too much about its consequences.
In certain contexts, the spontaneous is valued superlatively in relation to those who stick to reason.
Meanwhile, in bullfights or other sporting events, the use of this word is very frequent to refer to that individual who enters the field without having an authorization.
The synonym we use the most in this case is natural, because it precisely designates that which is neither feigned nor forced. Meanwhile, the word that directly opposes is that of forced, which refers to what is the result of force.
The quality of that which is characterized by being spontaneous, natural and sincere is designated as spontaneity, for example, is that the fact or person who has this quality will be considered spontaneous.
In another vein, in the chemistry, we can also find the concept of spontaneity, chemical spontaneity, which is that characteristic present in a substance and that will determine the conditions to develop a chemical reaction.