data file vs mug book

data file and mug book both are nouns.

Word	Noun	Adjective	Verb	Adverb
data file	Yes	No	No	No
mug book	Yes	No	No	No

As nouns, mug book is a hyponym of data file; that is, mug book is a word with a more specific, narrower meaning than data file:

data file: a set of related records (either written or electronic) kept together
mug book: a file of mug shots (pictures of criminals that are kept on file by the police)

Other hyponyms of data file include computer file, mug file, tickler, tickler file, editorial file.

data file (noun)	mug book (noun)
a set of related records (either written or electronic) kept together	a file of mug shots (pictures of criminals that are kept on file by the police)