[with object] 1  1Make the movement or flow in (a passage, pipe, road, etc.) difficult or impossible. ‘block up the holes with sticky tape’. 2  2Impress text or a design on (a book cover). ‘Original blue cloth, spine lettered and blocked in gold.’. 3  3Shape or reshape (a hat) on a mould. ‘nobody cleans and blocks old felt hats any more’.