groundwater pump vs submersible groundwater pump

groundwater pump and submersible groundwater pump both are nouns.

Word	Noun	Adjective	Verb	Adverb
groundwater pump	Yes	No	No	No
submersible groundwater pump	Yes	No	No	No

As nouns, groundwater pump and submersible groundwater pump are synonyms defined as:

groundwater pump and submersible groundwater pump: A pump suited for sampling and pumping underground water supplies.

groundwater pump (noun)	submersible groundwater pump (noun)
A pump suited for sampling and pumping underground water supplies.	A pump suited for sampling and pumping underground water supplies.