滑 slippery

(waterleft) + 骨 (bone)

★★☆☆☆

13 strokes

Onyomi

KATSU but not really

Mnemonic

You slipped on the water puddle and broke your bones.

Kunyomi

す*べる	to slip or pratfall ★★☆☆☆
す＊べりやすい	careful! It's slippery! ★★★☆☆

Jukugo

円滑(えんかつ) な

effortless/smooth ☆☆☆☆☆
円 (yen/circle) + 滑 (slippery) = 円滑 (effortless/smooth)

smooth, as in trouble-free and effortless.