pickup truck vs motortruck

pickup truck and motortruck both are nouns.

Word	Noun	Adjective	Verb	Adverb
pickup truck	Yes	No	No	No
motortruck	Yes	No	No	No

As nouns, motortruck is a hypernym of pickup truck; that is, motortruck is a word with a broader meaning than pickup truck:

Other hypernyms of pickup truck include truck.

pickup truck (noun)	motortruck (noun)
a light truck with an open body and low sides and a tailboard	an automotive vehicle suitable for hauling