show window vs shopwindow

show window and shopwindow both are nouns.

Word	Noun	Adjective	Verb	Adverb
show window	Yes	No	No	No
shopwindow	Yes	No	No	No

As nouns, show window and shopwindow are synonyms defined as:

show window and shopwindow: a window of a store facing onto the street; used to display merchandise for sale in the store

Other synonyms of show window include display window, shop window.

show window (noun)	shopwindow (noun)
a window of a store facing onto the street; used to display merchandise for sale in the store	a window of a store facing onto the street; used to display merchandise for sale in the store
a setting in which something can be displayed to best effect