-en¹

Forming verbs from nouns and adjectives.

Old English ‑nian, of Germanic origin.

Such verbs have the sense of creating, developing, or intensifying the state signalled in the noun or adjective from which they derive. Examples from adjectives include brighten, cheapen, fasten, loosen, moisten, redden, sweeten, and widen. Examples from nouns include: frighten, heighten, lengthen, strengthen, and threaten. The ending is not active in the language.