This is the 1021st most frequent Japanese word.
イヤ
"イヤ" means "disagreeable" or "unpleasant."
イヤ is used here as an adjective (イヤだ) to express dislike or something unpleasant.
この服はイヤだな。
I dislike these clothes.
イヤ is used interjectively here to strongly reject something being discussed.
イヤ、その話は聞きたくない。
No, I don’t want to hear about that.
イヤ is utilized here in a phrase to denote the intention or emotion of dislike without directly claiming dislike.