obstruction (n.) Look up obstruction at Dictionary.com
1530s, from Latin obstructionem (nominative obstructio) "an obstruction, barrier, a building up," noun of action from past participle stem of obstruere "build up, block, block up, build against, stop, bar, hinder," from ob "in front of, in the way of" (see ob-) + struere "to pile, build" (see structure (n.)).