Sinker meaning : One who sinks something. A weight used in fishing to cause the line or net to sink. Any of several high speed pitches that have a downward motion near the plate; a two-seam fastball, a split-finger fastball, or a forkball. Sinker nail, used for framing in current construction. A doughnut; a biscuit. In knitting machines, one of the thin plates, blades, or other devices, that depress the loops upon or between the needles.