1. (v. t.) To block up; to stop up or close, as to obstruct a way or passage\; to place an obstacle in, or fill with obstacles or impediments that prevent or hinder passing; as, to obstruct a street; to obstruct the channels of the body.

2. (v. t.) To be, or come, in the way of; to hinder from passing; to stop; to impede; to retard; as, the bar in the harbor obstructs the passage of ships; clouds obstruct the light of the sun; unwise rules obstruct legislation.

arrest backpedal backwater bar barricade beat off bind block block out block up blockade bolt brake bung caulk check chink chock choke choke off choke up clip the wings clog clog up close close off close tight close up confine congest constipate constrict cork counter cover crowd curb dam dam up debar decelerate delay detain dog drag draw rein drive back ease off ease up fend fend off fill fill up forbid foul halt hamper hinder hold at bay hold back hold in check hold off hold up impede interfere with interrupt jam keep at bay keep back keep off lag let down let up lock lose ground lose momentum lose speed make late moderate obstipate occlude pack parry plug plug up preclude prevent prohibit push back put back rebuff reef rein in relax repel repulse retard set back shroud shut off shut out shut tight slack off slack up slacken slow slow down slow up spile squeeze squeeze shut stall stanch stave off stay stench stifle stop stop up stopper stopple strangle strangulate stuff stuff up suffocate take in sail throttle down turn aside ward off