Non-

pref.
  1. A prefix used in the sense of not; un-; in-; as in nonattention, or non-attention, nonconformity, nonmetallic, nonsuit.

The prefix non- may be joined to the leading word by means of a hyphen, or, in most cases, the hyphen may be dispensed with. The list of words having the prefix non- could easily be lengthened.