The reading きっこう comes from the on'yomi 拮 (きつ) and 抗 (こう). The small っ (促音便) is a common sound change when 拮 is followed by a k-sound. Incorrect readings like けっこう or かっこう mispronounce the first kanji. It describes a fierce, balanced competition where neither side easily gains an advantage, indicating rivalry.

拮 (きつ) と 抗 (こう) の音読み。拮の促音便で「きっ」となります。両者が互角の力で激しく競り合い、優劣がつかない状態のこと。