Block (verb)

Synonyms: block, hinder, hamper, hold back, obstruct

block: to prevent something from passing along something
Example: The pipe is blocked with dead leaves.  The crash blocked the road for
hours.

hinder: to make it difficult for someone to do something
Example: Snow hindered the efforts of the rescuers.

hamper: to prevent something from happening or moving normally
Example: Lack of funds is hampering our development project.  The heavy bags
hampered her progress.

hold back: not to go forwards, or stop someone or something from going forwards
Example: Most of the crowd held back until they saw it was safe.  The water was held back by a small bank of earth.

obstruct: to prevent someone from doing something
Example: He obstructed their plans by making many complaints.