Synonyms for demanding

arduous, challenging, difficult, exacting, fastidious, finicky, fussy, grueling, hard, high-pressure, hypercritical, inflexible, insistent, laborious, nitpicking, onerous, over-critical, over-exacting, over-particular, pernickety, persnickety, problematic, rigorous, strenuous, strict, tough, uncompromising, unyielding