Synonyms to set with thorns

abstruse, Herculean, abstract, arcane, arduous, beclouded, blind, brutal, buried, civilized, close, clouded, complex, complicated, concealed, covered, covert, critical, cultivated, cultured, deep, delicate, demanding, difficile, difficult, eclipsed, educated, encyclopedic, erudite, esoteric, exacting, formidable, hairy, hard, hard-earned, hard-fought, heavy, hermetic, hid, hidden, hypothetical, ideal, in a cloud, in a fog, in eclipse, in purdah, in the wings, incommunicado, intricate, jawbreaking, knotted, knotty, laborious, latent, learned, lettered, literate, mean, mysterious, no picnic, not easy, obfuscated, obscure, obscured, occult, operose, pansophic, polyhistoric, polymath, polymathic, profound, recondite, rigorous, rough, rugged, scholarly, scholastic, secluded, secluse, secret, sequestered, severe, spiny, steep, strenuous, studious, thorny, ticklish, toilsome, tough, transcendental, tricky, under an eclipse, under cover, under house arrest, under wraps, underground, unknown, uphill, wicked, wise, wrapped in clouds, abrupt, backbreaking, burdensome, compl