Webster's Revised Unabridged Dictionary · 1913

Uncurl

Uncurl , transitive verb

[1st pref. un- + curl.]

To loose from curls, or ringlets; to straighten out, as anything curled or curly.
He sheaths his paw, uncurls his angry mane. — Dryden

Uncurl , intransitive verb

To become uncurled, or straight.