lineup vs police lineup

lineup and police lineup both are nouns.

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

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

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

Other synonyms of lineup include identity parade.

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