spontaneous

adj

1. natural, instinctive, unconscious, intuitive, Sl. gut, Sl. seat-of-the-pants; reflex, reflexive, involuntary, automatic, mechanical; compulsive, uncontrollable, irresistible; impulsive, impetuous, blind, rash, snap.

2. free, open, effortless; voluntary, willing, unrestrained; unconstrained, unforced, uncompelled; unprompted, unbidden, unasked for, unrequested, gratuitous.

3. unpremeditated, unplanned, unstudied, unprepared, unrehearsed; immediate, offhand, extemporaneous, extempore, extemporary, extemporized, spur-of-the-moment, on-the-spot, ad-lib, impromptu, Inf. off-the-cuff; unwitting, unknowing, unthinking, unguarded, unintentional.

4. self-acting, self-induced, independent; self-directing, self-moving, self-determined; self-initiated, self-generating, Biol. parthenogenic.

5.(usu. of vegetation) uncultivated, wild, in a natural state, native, unadorned; untended, untouched, overrun, overgrown; dense, lush, luxuriant, rank, flourishing.