From *proβwos (“correct”) + *-ēd (adverb-forming suffix). *<span class="searchmatch">proβwēd</span> correctly, properly, rightly *ən-proβw-ēd (“incorrectly, improperly”) Latin: improbē...
adverbs from o/ā-stem adjectives: -ly *proβwos (“correct”) + *-ēd → *<span class="searchmatch">proβwēd</span> (“correctly”) Latin: -ēd (Old Latin), -ē (Classical Latin) Osco-Umbrian:...