The Collaborative International Dictionary
Pirl \Pirl\, v. t. [Cf. Purl.]
To spin, as a top.
To twist or twine, as hair in making fishing lines.
Douglas Harper's Etymology Dictionary
c.1500 (implied in pirled) "to twist, wind" (thread, etc.), of unknown origin. Related: Pirling.
n. a ripple; a twist or curl vb. 1 to twist or wind, especially into a cord or braid etc. 2 to ripple, swirl, especially of water 3 (context transitive English) to cause to revolve or spin