The Collaborative International Dictionary of English v.0.48:
Hack \Hack\, v. t. [imp. & p. p. Hacked (h[a^]kt); p. pr. &
vb. n. Hacking.] [OE. hakken, AS. haccian; akin to D.
hakken, G. hacken, Dan. hakke, Sw. hacka, and perh. to E.
hew. Cf. Hew to cut, Haggle.]
1. To cut irregulary, without skill or definite purpose; to
notch; to mangle by repeated strokes of a cutting
instrument; as, to hack a post.
My sword hacked like a handsaw. --Shak.
2. Fig.: To mangle in speaking. --Shak.
3. (Computers) To program (a computer) for pleasure or
compulsively; especially, to try to defeat the security
systems and gain unauthorized access to a computer.
4. To bear, physically or emotionally; as, he left the job
because he couldn't hack the pressure. [Colloq.]