WordWeb Online

1. Preventing movement
   "the impeding crowds of revelers overflowing into the street"
   - clogging, hindering, obstructive

1. Be a hindrance or obstacle to
   "She is impeding the progress of our project"
   - hinder
    
2. Block passage through
   "impede the path"
   - obstruct, obturate, occlude, jam, block, close up

See also: impediment, preventative, preventive

Type of: keep, prevent