impromptu

a./ad.无准备的(地)；即兴的(地)

impress, impress...on, impressed, impression, impressionability, impressionable, impressionism, impressions, impressive, impressively, impressiveness, imprimatur, imprint, imprinting, imprison, imprisonment, improbability, improbable, improbably, improbity, improper, improper fraction, improperly, impropriety, improve, improve on, improvement, improvidence, improvident, improvidently, improvisation, improvise, improvised, imprudence, imprudent, imprudently, impudence, impudent, impudently, impugn,