Word parts hostile + -ity Pronunciation (UK) IPA (key): /hɒˈstɪlɪti/ (US) IPA (key): /hɑˈstɪlɪti/ Audio (US)(file) Noun Singular hostility Plural hostilities (countable & uncountable) Hostility is a negative action or feeling against something or somebody. Synonym: hatred He wanted to reach an agreement, but her hostility was difficult to deal with. Related words hostileWikiwand - on Seamless Wikipedia browsing. On steroids.