1) Bar 2) Barricado 3) Block 4) Burden 5) Congest 6) Dam 7) Deter 8) Frustrate 9) Hamper 10) Hinder 11) Interfere 12) Limit 13) Obturate 14) Occlude 15) Prevent 16) Short circuit 17) Slow 18) Stop 19) Stymie 20) Tie 1) Be a hindrance or obstacle to 2) Be a roadblock to 3) Block 4) Block passage through 5) Block, obstruct 6) Get in the way of 7) Hamper 8) Hinder 9) Hinder get in the way of 10) Hold back 11) Keep 12) Obstruct 13) Obstruct or hinder 14) Obstruct progress 15) Occlude 16) Prevent 17) Rascal notes hamper 
• (v. t.) To hinder; to stop in progress; to obstruct; as, to impede the advance of troops.
Im·pede' transitive verb [ imperfect & past participle Impeded ; present participle & verbal noun Impeding .] [ Latin impedire , lit., to entangle the feet; prefix im- in + pes , pedis , foot. See Foot
hinder get in the way of 
[v] - be a hindrance or obstacle to
impede 1. To retard in progress or action by putting obstacles in the way; to obstruct; to hinder; to stand in the way of. 2. The act of impeding; hindrance; impediment. The woman impedes the man`s efforts to escape from her control. —Word Info image © ALL rights reserved.
verb be a hindrance or obstacle to; `She is impeding the progress of our project`
to retard in movement or progress by means of obstacles or hindrances; obstruct; hinder.
[Difficult words] be a hindrance or obstacle to be a hindrance or obstacle to