Толковый словарь английского языка Oxford English Reference - slippery

adj. 1 difficult to hold firmly because of smoothness, wetness, sliminess, or elusive motion. 2 (of a surface) difficult to stand on, causing slips by its smoothness or muddiness. 3 unreliable, unscrupulous, shifty. 4 (of a subject) requiring tactful handling. Phrases and idioms slippery elm 1 the N. American red elm, Ulmus fulva. 2 the medicinal inner bark of this. slippery slope a course leading to disaster. Derivatives slipperily adv. slipperiness n. Etymology: prob. coined by Coverdale (1535) after Luther's schlipfferig, MHG slipferig f. slipfern, slipfen f. Gmc: partly f. slipper slippery (now dial.) f. OE slipor f. Gmc