IPA: /pərˈjuːzər/
KK: /pɜrˈjuːzər/
A person who reads or examines something carefully and in detail.
The peruser of the document found several important details that others missed.
This word originates from the combination of 'per-' (meaning through) and 'user' (from Old French 'user', meaning to use). The word 'peruser' means someone who uses something thoroughly or carefully, often in the context of examining or reading closely.
Think of someone who goes 'through' ('per-') a text or document to 'use' it ('user') carefully — that's why a peruser is someone who examines something closely.