Hand radical on the left, side-form of 手. It marks a hand action — picking out, singling out, prying loose. Same family as 挑 to pick, 择 to select (its partner in 抉择), 挖 to dig.
Right side 夬 supplies the sound (guài → jué) and a fitting hint of 'decisiveness.' Same phonetic in 决 to decide and 缺 lacking — note the shared sense of cutting things off cleanly.