source: Roadblock - Pokémemes - Pokémon, Pokémon GO

HINDER, IMPEDE, OBSTRUCT, BLOCK mean to interfere with the activity or progress of.

HINDER stresses causing harmful or annoying delay or interference with progress.

e.g. rain hindered the climb

IMPEDE implies making forward progress difficult by clogging, hampering, or fettering.

e.g. tight clothing that impedes movement

OBSTRUCT implies interfering with something in motion or in progress by the sometimes intentional placing of obstacles in the way.

e.g. the view was obstructed by billboards

BLOCK implies complete obstruction to passage or progress.

e.g. a landslide blocked the road

verb with object

block (an opening, path, road, etc.); be or get in the way of:

〈道路･通路〉をふさぐ, 〈人･乗り物の通行〉を妨害する

e.g. she was obstructing the entrance.

prevent or hinder (movement or someone or something in motion):

e.g. they had to alter the course of the stream and obstruct the natural flow of the water.

deliberately make (something) difficult:

〈流れ･行為〉を妨げる, 困難にする, 〈視野･光など〉をさえぎる

e.g. fears that the regime would obstruct the distribution of food.

Law commit the offense of intentionally hindering (a legal process).

(in various sports) impede (a player in the opposing team) in a manner which constitutes an offense.

obstructor |-tər| noun

late 16th century: from Latin obstruct- ‘blocked up’, from the verb obstruere, from ob- ‘against’ + struere ‘build, pile up’.