in ‧ ten ‧ si ‧ fi ‧ er /ɪnˈtensəfaɪə, ɪnˈtensɪfaɪə $ -ər/ BrE AmE noun [countable] technical
a word, usually an adverb, that is used to emphasize an adjective, adverb, or verb, for example the word ‘absolutely’ in the phrase ‘that’s absolutely wonderful’