Entry 2 senses · 2 variants Webster, 1913 Proin /(proin)/ · IPA /pɹɔɪn/ v. t. v. i. 01 v. t. To lop; to trim; to prune; to adorn. 1. To lop; to trim; to prune; to adorn.[Obs.] “The sprigs that did about it grow He proined from the leafy arms.” — Chapman. 02 v. i. To employed in pruning. 1. To employed in pruning.[Obs.]