A suffix signifying to make, to cause, used to form verbs from nouns and adjectives; as in strengthen, quicken, frighten. This must not be confused with -en corresponding in Old English to the AS. infinitive ending -an.
-EN
Meaning of -EN in English
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012