Excrescent /(?)/

Ex·cres·cent

Excrescent

a.
  1. Growing out in an abnormal or morbid manner or as a superfluity.
    Expunge the whole, or lip the excrescent parts.

Phrases & Compounds
Excrescent letter
a letter which has been added to a root; as, the d in alder (AS. alr) is an excrescent letter.