Herculean abstruse adverse antagonistic arduous awkward baffling beyond one bloody-minded brutal burdensome cantankerous complex complicated conflicting contrary counter counteractive crabbed cramp critical cross-grained dark delicate demanding detrimental difficile effortful enigmatical exacting fastidious finical finicking finicky finikin formidable froward fuss-budgety fussy garbled grim hairy hard hard to please hard to understand hard-earned hard-fought harmful hostile ill-behaved in opposition inimical intractable intricate irascible jawbreaking jumbled knotted knotty labored laborious mean miserable naughty nit-picking no picnic not easy obfuscated obscure obscured obstinate obstructive onerous operose opposed opposing opposite ornery overtechnical particular pawky pernickety perplexed perplexing persnickety perverse problem problematic problematical profound puzzling queasy recalcitrant recondite refractory rigorous rough rugged scabrous scrambled sensitive set with thorns severe sinister spiny squeamish steep strenuous stressful stubborn stuffy sulky sullen thorny ticklish toilsome tough tricky troubled troublesome troubling troublous trying unaccommodating uncompromising unfavorable unmanageable untoward unyielding uphill wayward wicked wretched wrongheaded