Excrescent \Ex*cres"cent\, a. [L. excresens, -entis, p. pr. of excrescere to grow out; ex out + crescere to grow. See {Crescent}.] Growing out in an abnormal or morbid manner or as a superfluity. Expunge the whole, or lip the excrescent parts. --Pope. {Excrescent letter} (Philol.), a letter which has been added to a root; as, the d in alder (AS. alr) is an excrescent letter.