spontaneous
Pronunciation:
/spɒnˈteɪ.ni.əs//spɑnˈteɪ.ni.əs/adjective
Definitions
Self-generated; happening without any apparent external cause.
Example: He made a spontaneous offer of help.
Done by one's own free choice, or without planning.
Proceeding from natural feeling or native tendency without external or conscious constraint
Arising from a momentary impulse