忌 is built from the 己 and 心 components.
It reads キ like 己, as do 記, 起, and 紀 — learn 己 once and the family's reading comes with it.
A common word using 忌 is 回忌 (かいき), meaning “death anniversary; anniversary of a person's death”.
Kanji that look similar include 改, 妃, 巻, and 紀.
