ADJECTIVE (3)

1. not secured within a cover;
- Example: "an unbound book"

2. not restrained or tied down by bonds;

3. not held in chemical or physical combination;

The Collaborative International Dictionary of English v.0.48:

Unbind \Un*bind"\ ([u^]n*b[imac]nd"), v. t. [imp. & p. p.
   Unbound ([u^]n*bound"); p. pr. & vb. n. Unbinding.] [AS.
   unbindan. See Un-, and Bind.]
   To remove a band from; to set free from shackles or
   fastenings; to untie; to unfasten; to loose; as, unbind your
   fillets; to unbind a prisoner's arms; to unbind a load.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Unbound \Un*bound"\,
   imp. & p. p. of Unbind.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unbound
    adj 1: not secured within a cover; "an unbound book" [ant:
           bound]
    2: not restrained or tied down by bonds [ant: bound]
    3: not held in chemical or physical combination