IPA: /ˈstɪk.lər/
KK: /ˈstɪk.lɚ/
A person who demands that things be done in a certain way or insists on strict adherence to rules or standards.
She is a stickler for punctuality and expects everyone to arrive on time.
Stickler → The word originates from the Middle English *stickler*, which is derived from the verb 'stickle' (meaning to argue or dispute) and the suffix '-er' (meaning a person who). A stickler is a person who insists on a certain quality or detail, often to the point of being pedantic or overly meticulous.
Think of someone who 'argues' or 'disputes' ('stickle') about details — that's why a stickler is someone who insists on precision.