[c]/ˈbrutəlaɪz/ (say 'broohtuhluyz)

verb (brutalised, brutalising)
verb (t)
1. to make brutish: *How habitual sin and misery suffice to brutalize `the human face divine'! –marcus clarke, 1874.
2. to treat in a brutal fashion: to brutalise the slaves.
verb (i)
3. to make someone brutish: *it is true that servitude, except when it actually brutalises, though corrupting to both, is less so to the slaves than to the slavemasters. –junie morosi, 1975.
Also, brutalize. –brutalisation /ˌbrutəlaɪˈzeɪʃən/ (say .broohtuhluy'zayshuhn), noun
Usage: The basic sense of this word in its transitive use is `to make brutal' meaning `to cause to become brutish in behaviour'. There is another meaning which has had currency since the late 18th century – `to treat in a brutal fashion'. Although there are still those who feel that this second meaning is incorrect, it is given without comment in major English dictionaries and there is corpus evidence of its use in Australian English.

Australian English dictionary. 2014.