pisser vs wetter

pisser and wetter both are nouns.

Word	Noun	Adjective	Verb	Adverb
pisser	Yes	No	No	No
wetter	Yes	No	No	No

As nouns, wetter is a hyponym of pisser; that is, wetter is a word with a more specific, narrower meaning than pisser:

pisser: a person who urinates
wetter: someone suffering from enuresis; someone who urinates while asleep in bed

Other hyponyms of pisser include bed wetter, bedwetter.

pisser (noun)	wetter (noun)
a very disagreeable difficulty	a workman who wets the work in a manufacturing process
a person who urinates	someone suffering from enuresis; someone who urinates while asleep in bed
	a chemical agent capable of reducing the surface tension of a liquid in which it is dissolved