slippery, slide, slip, fail exam
滑 centers on a lack of friction that makes movement uncontrolled: slipping, sliding, or being slippery. The idea extends naturally to failing an exam as a figurative slip or slide off the expected path.
滑 combines 氵 (water) with 骨 (bone), likely as a phono-semantic compound where 骨 contributes the sound and water suggests slipperiness. The exact historical development is uncertain, but the water component fits the slippery meaning well.
Water 氵 on bones 骨 makes them slick and slippery. Imagine trying to hold a wet bone—it slides right out of your hand.
For カツ, picture a cat slipping on a wet bone: cat -> カツ, and the cat slides across the floor.
to slide; to glide; to skate; to ski
slime; sliminess; mucus; viscous liquid
gliding; sliding; skating (on ice); skiing; glide; slide
smooth (of a surface); glassy; velvety; soft
funny; comical; humorous; laughable
smooth; undisturbed; uninterrupted; harmonious
lubrication; smoothness
(playground) slide
nameko (var. of mushroom) (Pholiota nameko)
sliding; slipping
gliding (through the air)
flat and smooth
start; beginning
pulley; block; tackle
sliding down (a slope, mountainside); slipping down
sliding
sideslip; skid; sliding sideways
descent (esp. in skiing); sliding down; skiing down
to slip off
to let slip; to slide; to glide