arch·en·e·my 
(ärch-ĕnə-mē)
(ärch-ĕnə-mē)n.
1. A principal enemy.
2. often Archenemy The Devil; Satan. Used with the.
- un-
- un-
- unabashed
- unabashedly
- unabated
- unabatedly
- unable
- unabridged
- unaccented
- unacceptability
- unacceptable
- unacceptably
- unaccommodated
- unaccompanied
- unaccomplished
- unaccountability
- unaccountable
- unaccountably
- unaccounted-for
- unaccredited
- unaccustomed
- unaccustomedly
- unachievable
- unacknowledged
- una corda