Noun, Na-adjective (keiyodoshi), Suru verb, Intransitive verb
spoiled fun; loss of interest; damper (e.g. on the party); wet blanket; turn-off
興ざめの人も、よく知るようになると、かならずしも不快ではない。Wet blankets are not always unpleasant after you get to know them.
Also written 興醒め【きょうざめ】、興冷め【きょうざめ】、興覚め【きょうざめ】