The Collaborative International Dictionary of English v.0.48:
Imperforate \Im*per"fo*rate\, Imperforated \Im*per"fo*ra"ted\, a. [L. pref. im- not + perforatus, p. p. of perforate to perforate. See Perforate.] Not perforated; having no opening or aperture. --Sir J. Banks. [1913 Webster]WordNet (r) 3.0 (2006):
imperforate adj 1: not perforated; having no opening