police lineup vs lineup

police lineup and lineup both are nouns.

Word	Noun	Adjective	Verb	Adverb
police lineup	Yes	No	No	No
lineup	Yes	No	No	No

As nouns, police lineup and lineup are synonyms defined as:

police lineup and lineup: a line of persons arranged by police for inspection or identification

Other synonyms of police lineup include identity parade.

police lineup (noun)	lineup (noun)
a line of persons arranged by police for inspection or identification	(baseball) a list of batters in the order in which they will bat
	the schedule of programs for a particular period
	a line of persons arranged by police for inspection or identification