From Longman Dictionary of Contemporary Englishblock sth↔ off phrasal verbTTRSCPto completely close something such as a road or an opening Police blocked off the city centre streets. The fireplace had been blocked off. → block→ See Verb table
Examples from the Corpus
block off• When they did, traffic got worse; then they blocked it off and traffic improved.• The service block comes off at a right angle at the back and forms a sort of court where you arrive.• I saw the car away up the block, turning off Fifth, probably coming back to inspect their work.• It's a good idea, but why block it off for certain limited hours?• The Scarlet Letter blocks went off in March.• They had blocked the street off, rather as if an armed siege was in progress.• The cell block stood just off the L-shaped charge room, a corridor almost completely without daylight.• It would be easy, Wheeler said, to block the ditch off to trap the pollutant. 