Something, usually abnormal, which grows out of something else. / A disfiguring or unwanted mark or adjunct.

plural of excrescence

A growing mutation, usually abnormal. / (phonetics) A sound in a word without etymological reason.

Growing out in an abnormal or morbid manner or as a superfluity.

plural of excrescent

plural of excrescency

An excrescent state or condition; the quality or fact of growing out of something; abnormal or excessive development / (obsolete) An exuberant outburst; an extravagance.

In an excrescent manner.