The Collaborative International Dictionary
Proin
Proin \Proin\, v. i. To employed in pruning. [Obs.]
Proin
Proin \Proin\ (proin), v. t. [See Prune to trim.]
To lop; to trim; to prune; to adorn. [Obs.]
--Chaucer.
The sprigs that did about it grow
He proined from the leafy arms.
--Chapman.
Wiktionary
proin
vb. (obsolete form of prune English)