Bio-hacker: a person who surrupticiously/clandestinely discerns the biological features of a subject and creates a fascimile to subvert biologically coded safeguards. Alternately, a bio-hacker surrupticiously or unconscentually changes the biological features of a subject, whether for nefarious or neutral purpose. In the former sense, movies depicting people gaining unauthorized access by imitating fingerprints, irises, or genetic material involve a bio-hacker. A story involving a character launching a mutagenic attack or even a beneficial biological change, as in Captain America's origin, employs a bio-hacker.
I discovered the biohacker nodeshell and wrote the above definition. I drew mainly from Paul McAuley’s short story “Gene Wars.” The story shows snippets of the protagonist, Evan, entire life and involvement in the genetic revolution. The particularly relevant scene is a quiet contest between him and a “gene pirate.” Clandestinely representing a pharmaceutical company, Evan’s tailored immune system foils the pirate’s “zombie virus.” He opts instead for "slow poison" and steals, then sabotages the pirate’s work.
However, the current Wikipedia article about biopunk describes a lighter version of biohacker. That author reserves biohacking for hobbyists, like the character Uncle Mycroft of Jasper FForde’s Thursday Next series. In his fiction, people have reengineered dodos, mammoths, and Neanderthals. For example, some of the work was done by hobbyists rather than dedicated companies, so there are varieties of dodos (early versions derived from pigeons didn’t have wings).
The argument is moot until biohackers leave the page and begin to harry or amuse us.