WordNet (r) 3.0 (2006):
block off v 1: obstruct access to [syn: blockade, block off] 2: render unsuitable for passage; "block the way"; "barricade the streets"; "stop the busy road" [syn: barricade, block, blockade, stop, block off, block up, bar] 3: block off the passage through; "We shut off the valve" [syn: shut off, block off, close off]