Select the option that can be used as a one-word substitute for the given group of words.
A person who compiles a dictionary

Correct option is D

The correct one-word substitute for "a person who compiles a dictionary" is "Lexicographer."
 A lexicographer is someone who compiles, writes, or edits dictionaries.

Example: Samuel Johnson was a renowned lexicographer who compiled one of the most important dictionaries of the English language.

The other options do not fit this description:
 "Plagiarist" refers to a person who uses someone else's work or ideas and passes them off as their own.
 "Iconoclast" is someone who attacks or criticizes cherished beliefs or institutions.
 "Bibliophile" denotes a person who has a great love for books.
 Therefore, option (d) "Lexicographer" is the appropriate choice.