borer

noun8

1. •
   A tool used for drilling.
2. •
   An insect or insect larva that bores into wood.
3. •
   One of the many types of mollusc that bore into soft rock.
4. •
   A cyclostome, such as a hagfish, which bores into injured, dead, or decaying sea creatures to feed on their flesh.
5. •
   A person who bores or drills; a person employed to drill bore holes.
6. •
   A tedious person, who bores others; a bore.

   • The boree has been heard from frequently since the Renaissance, and his sentiments have undergone little change. The borer hasn't had much to say for himself. — 1896
7. •
   The penetrating root of a parasitic plant.
8. •
   (slang) A knife fit for a stabbing.