fe·ral 
(fîrəl, fĕr-)
(fîrəl, fĕr-)adj.
1.
a. Having returned to an untamed state from domestication: a pack of feral dogs.
b. Existing in a wild or untamed state.
2. Of or suggestive of a wild animal; savage: a feral grin.
[From Latin fera, wild animal, from ferus, wild; see ghwer- in the Appendix of Indo-European roots.]