leech

noun

1. Archaic a physician
2. any of a subclass (Hirudinea) of mostly flattened, annelid worms living in water or wet earth and having a well-developed sucker at each end: most are bloodsuckers, and one species (Hirudo medicinalis) has been used in medicine, esp. in former times, to bleed patients
3. a person who clings to another to gain some personal advantage; parasite

transitive verb

1. Obsolete to heal
2. to apply leeches to; bleed with leeches
3. to cling to (another) as a parasite; drain dry

intransitive verb

noun

1. the after edge of a fore-and-aft sail
2. either of the vertical edges of a square sail