Entry 3 senses · 2 variants Webster, 1913 brutalise · IPA /ˈbɹuːt(ə)lʌɪz/ v. t. v. i. 01 v. t. to treat brutally. 1. to treat brutally. 2. to cause to become like a brute; as, life in the concentration camp had brutalised him. Syn. brutalize. — Syn. -- brutalize. 02 v. i. to become brutal. 1. to become brutal. Syn. brutalize.