Sinker

noun

1. One who sinks something.
2. A weight used in fishing to cause the line or net to sink.

   "Hook the sinker onto this loop."

3. 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.

   "His sinkers drew one ground ball after another."

4. Sinker nail, used for framing in current construction.
5. A doughnut; a biscuit.