3 synonym groups for Challenging

in a bind, in a jam, in a pickle, in a fix, in a tight spot, in a tight corner, in hot water, in trouble, in a predicament, in a quandary, in a dilemma, in dire straits, in a mess, in a spot, in a scrape, in a pinch, in a hole, in a bad way, up against it, up the creek, between a rock and a hard place, in a sticky situation, in a tricky situation, in a tough spot, in a tough position, in a challenging situation, in a complicated situation, in a knot, in a muddle, in a quagmire, in a crisis, in a plight, in a conundrum [x]

Insoluble problem, intractable problem, insurmountable problem, stubborn problem, unresolvable problem, unmanageable problem, unfixable problem, unrectifiable problem, unrepairable problem, uncorrectable problem, unalterable problem, unchangeable problem, unmovable problem, unbudgeable problem, unrelenting problem, unbending problem, unyielding issue, intractable issue, insurmountable issue, stubborn issue, unresolvable issue, unmanageable issue, unfixable issue, unrectifiable issue, unrepairable issue, uncorrectable issue, unalterable issue, unchangeable issue, unmovable issue, unbudgeable issue, unrelenting issue, unbending issue [x]

challenging, exacting, tough, rigorous, stringent, taxing, arduous, difficult, hard, strict, pressing, insistent, forceful, assertive, commanding, imperious, exigent, picky, fussy, choosy, critical, particular, meticulous, fastidious, high-maintenance, laborious, burdensome, onerous, weighty, heavy [x]