- obstacle, obstruction - something immaterial that stands in the way and must be circumvented or surmounted; "lack of immagination is an obstacle to one's advancement"; "the poverty of a district is an obstacle to good education"; "the filibuster was a major obstruction to the success of their plan"
--1 is a kind of hindrance, deterrent, impediment, balk, baulk, check, handicap
--1 has particulars:barrier, roadblock; hang-up, hitch, rub, snag; hurdle; stymie - obstacle - an obstruction that stands in the way (and must be removed or surmounted or circumvented)
--2 is a kind of obstruction, obstructor, obstructer, impediment, impedimenta
--2 has particulars: hazard; stumbling block; water jump