This is a jukugo word that uses the on'yomi readings of the kanji. First up, notice that いち changes to いっ. And since you haven't learned the on'yomi for the kanji 蹴 (kick) yet, here's a mnemonic to help you:
When you're planning to flatly reject someone, one kick is all you need. Before you do that, be absolutely sure to put your shoe (しゅう) on first.
I confessed my love to Koichi, but he totally rejected me.
Viet beat the yokai easily.
I submitted a holiday request to my boss but it was flatly rejected.