IPA: /ɪnˈtɛnsɪfaɪər/
KK: /ɪnˈtɛnsɪfaɪər/
A word or phrase that is used to give more emphasis or strength to another word, often making it more intense or powerful.
In the sentence 'She is very happy', the word 'very' acts as an intensifier.
Intensifier → It is formed from "intens-" (from Latin "intensus", meaning stretched or strained) and "-ifier" (from Latin "-ificare", meaning to make or to do). The word "intensifier" refers to something that makes a quality stronger or more intense.
Think of something that 'stretches' ('intens-') a quality to make it stronger — that's what an intensifier does.