something, usually abnormal, which grows out of something else
(quote-text)|title=(w)|chapter=7|url=http://www.gutenberg.org/files/1260/1260-h/1260-h.htm|passage=I have again and again intimated that I desire the hair to be arranged closely, modestly, plainly. Miss Temple, that girl’s hair must be cut off entirely; I will send a barber to-morrow: and I see others who have far too much of the excrescence—that tall girl, tell her to turn round.
(quote-text)|title=(w)|chapter=7|url=http://www.gutenberg.org/files/215/215-h/215-h.htm|passage=The squirrels were in hiding. One only he saw,—a sleek gray fellow, flattened against a gray dead limb so that he seemed a part of it, a woody excrescence upon the wood itself.
(quote-text)|title=(w)|chapter=31|url=http://www.gutenberg.net.au/ebooks01/0100171h.html|passage=It is taken for granted that a beggar does not 'earn' his living, as a bricklayer or a literary critic 'earns' his. He is a mere social excrescence, tolerated because we live in a humane age, but essentially despicable.
a disfiguring or unwanted mark or adjunct
puhekieltä epenthesis of a consonant, e.g., (m) as ˈwɔrmpθ (adding a p between m and θ), or (m).