hairsplitting vs word-splitting

hairsplitting and word-splitting both are nouns.

Word	Noun	Adjective	Verb	Adverb
hairsplitting	Yes	Yes	No	No
word-splitting	Yes	No	No	No

As nouns, hairsplitting and word-splitting are synonyms defined as:

hairsplitting and word-splitting: making too fine distinctions of little importance

hairsplitting (noun)	word-splitting (noun)
making too fine distinctions of little importance	making too fine distinctions of little importance

hairsplitting (adjective)	word-splitting (adjective)
developed in excessively fine detail