pisser vs difficultness

pisser and difficultness both are nouns.

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

As nouns, difficultness is a hypernym of pisser; that is, difficultness is a word with a broader meaning than pisser:

pisser: a very disagreeable difficulty
difficultness: the quality of being almost beyond one's ability to deal with and requiring a great effort to achieve a positive result

Other hypernyms of pisser include difficulty.

pisser (noun)	difficultness (noun)
a very disagreeable difficulty	the quality of being almost beyond one's ability to deal with and requiring a great effort to achieve a positive result
a person who urinates