spontaneous — coming or resulting from a natural impulse or tendency; without effort or premeditation; natural and unconstrained; unplanned: a spontaneous burst of applause.
Four-or-more syllable rhymes
miscellaneous — consisting of members or elements of different kinds; of mixed character: a book of miscellaneous essays on American history.
percutaneous — administered, removed, or absorbed by way of the skin, as an injection, needle biopsy, or transdermal drug.
simultaneous — existing, occurring, or operating at the same time; concurrent: simultaneous movements; simultaneous translation.
Four-or-more syllable rhymes
contemporaneous — If two events or situations are contemporaneous, they happen or exist during the same period of time.
