stickler

[ stik-ler ]
/ ˈstɪk lər /

noun

a person who insists on something unyieldingly (usually followed by for): a stickler for ceremony.
any puzzling or difficult problem.

Origin of stickler

First recorded in 1530–40; stickle + -er1

Example sentences from the Web for stickler

British Dictionary definitions for stickler

stickler
/ (ˈstɪklə) /

noun

(usually foll by for) a person who makes insistent demands a stickler for accuracy
a problem or puzzle the investigation proved to be a stickler