(slang) An imitation of the sound of gagging, used to express disgust or disdain blech 151 up, 11 down buy blech mugs, tshirts and magnets an expression such as disgusting, yucky, horrid, gross...usually in taste. Melissa "Blech! that shirt with those jeans makes me want to gag!" -or- Susan "Blech! eww, this pizza tastes rancid!" yuck 176 up, 25 down buy yuck mugs, tshirts and magnets something ..