IPA: /ˈkætɪˌkaɪzər/
KK: /ˈkætɪˌkaɪzər/
A person who teaches or instructs others, especially in religious matters, using a question-and-answer format.
The catechizer helped the children understand the basics of their faith.
Catechizer is formed from "catechize" (from Greek "katēkhizō", meaning to instruct orally) and "-er" (meaning a person who). A catechizer is a person who instructs or teaches, especially in a religious context.
Think of someone who 'instructs orally' — 'catechize' means to teach, and '-er' indicates a person. A catechizer is someone who teaches or instructs.