Sentence:  The utmost they aimed at doing was thoroughly to clear the old Church of all the corruptions and superstitions which had disfigured it in the course of ages, and which, like the flaunting ivy <WSD>overgrowing</WSD> some ancient building [...] 
Meaning of the word marked with <WSD> tags:  To grow over; (of one thing) to cause (a second thing) to become overgrown (with or by the first thing).