obstructer

transitive verb

1. to block or stop up (a passage) with obstacles or impediments; dam; clog
2. to hinder (progress, an activity, etc.); impede
3. to cut off from being seen; block (the view)

Origin: < L obstructus, pp. of obstruere, to block up, build against < ob- (see ob-) + struere, to pile up: see strew