Any obstacle or impediment.

Roget 704: difficulty; hardness etc. adj.; impracticability etc. (impossibility) 471; tough work, hard work, uphill work; hard task, Herculean task, Augean task^†; task of Sisyphus, Sisyphean labor, tough job, teaser, rasper^†, dead lift.    dilemma, embarrassment; deadlock; perplexity etc. (uncertainty) 475; intricacy; entanglement, complexity etc. 59; cross fire; awkwardness, delicacy, ticklish card to play, knot, Gordian knot, dignus vindice nodus [Lat.], net, meshes, maze; coil etc. (convolution) 248; crooked path; involvement.    nice point, delicate point, subtle point, knotty point; vexed question, vexata quaestio [Lat.], poser; puzzle etc. (riddle) 533; paradox; hard nut to crack, nut to crack; bone to pick, crux, pons asinorum [Lat.], where the shoe pinches.    nonplus, quandary, strait, pass, pinch, pretty pass, stress, brunt; critical situation, crisis; trial, rub, emergency, exigency, scramble.    scrape, hobble, slough, quagmire, hot water, hornet's nest; sea of troubles, peck of troubles; pretty kettle of fish; pickle, stew, imbroglio, mess, ado; false position.    set fast, stand, standstill; deadlock, dead set.    fix, horns of a dilemma, cul de sac [Fr.]; hitch; stumbling block etc. (hindrance) 706.    [difficult person] crab; curmudgeon.    ... show more